T23c round 1 fix

- suggestions: arrows step past disabled rows and scroll the cursor into view;
  the cursor starts on an enabled row; Enter refuses a disabled one
- active_trigger takes the query's word test: one word for mentions, any
  non-space for the composer, so a file name keeps its dot
- DragDropOverlay takes the drop itself, which gives it the hitbox gpui needs
  to style a drag-over
- ParameterPanel shows the places of the step, value and both ends
- gallery: the prompt menu fills the draft; Reset restores the system prompt
- AGENTS: drag-over styles need a hitbox; debug_bounds never clear

AGENTS.md

@@ -129,6 +129,8 @@ Ely GPUI Component. A component library for GPUI, in light and dark.
 - Clippy's `single_range_in_vec_init` rejects `[a..b]` and `vec![a..b]`; bind the range first.
 - A component built on `lists::Tree` fills its box; the host gives it a height. A fixed-width column beside a `flex_1` one takes `flex_none`, or it shrinks.
 - Editor rows read their text through `CodeEditor::row_text`: a multi-line ghost cuts its line, and the rest follows the ghost's last line.
+- gpui styles a drag-over only on an element with its own hitbox. A veil that shows while files hover takes the drop itself (`chat::DragDropOverlay`).
+- gpui 0.2.2 never clears `debug_bounds`: a test sees an element appear, not leave.
 
 ## Decisions
 

TASKS.md

@@ -261,3 +261,4 @@ Per-component lines live in `tasks/`. Tags there:
 | T23b | 1 | FAIL | source cards and web results with a handler were no Tab stops; in a narrow column the sources row and a passage's header ran past their edge |
 | T23b | 2 | FAIL | the gallery's narrow passage built a vec of one range, which clippy refuses, so the checks failed |
 | T23b | 3 | PASS | |
+| T23c | 1 | FAIL | suggestion arrows landed on disabled rows and left the cursor out of view; a dot ended a file mention; the drop veil never showed, since gpui styles a drag-over only on an element with a hitbox; a parameter's places came from its step alone; the gallery's prompt menu and Reset only logged |

examples/gallery/pages/chat/compose.rs

@@ -29,13 +29,15 @@ macro_rules! asset {
     };
 }
 
-fn field(key: &'static str, text: &str, window: &mut Window, cx: &mut App) -> Entity<TextInput> {
-    let text = text.to_string();
-    window.use_keyed_state(key, cx, move |window, cx| {
+const SYSTEM: &str = "You answer about color in plain words. Cite sources.";
+
+/// The composer's text, which the prompt menu fills.
+pub fn draft(window: &mut Window, cx: &mut App) -> Entity<TextInput> {
+    window.use_keyed_state("chat-compose", cx, |window, cx| {
         let mut input = TextInput::new(window, cx)
             .multi_line(1, 8)
             .placeholder("Ask anything, / for commands, @ for context");
-        input.set_text(text, cx);
+        input.set_text("Compare these two lifts in dark mode", cx);
         input
     })
 }
@@ -64,13 +66,11 @@ fn attachments() -> Vec<Attachment> {
     ]
 }
 
-pub fn composer(window: &mut Window, cx: &mut App) -> impl IntoElement + use<> {
-    let draft = field(
-        "chat-compose",
-        "Compare these two lifts in dark mode",
-        window,
-        cx,
-    );
+pub fn composer(
+    draft: &Entity<TextInput>,
+    window: &mut Window,
+    cx: &mut App,
+) -> impl IntoElement + use<> {
     let files = keep("chat-attachments", attachments, window, cx);
     let context = keep(
         "chat-context",
@@ -131,7 +131,7 @@ pub fn composer(window: &mut Window, cx: &mut App) -> impl IntoElement + use<> {
         set(files, next, cx)
     };
     let (sent, stopped, mentioned) = (busy.clone(), busy.clone(), context.clone());
-    let mut input = PromptInput::new("chat-composer", &draft, move |_, cx| set(&sent, true, cx))
+    let mut input = PromptInput::new("chat-composer", draft, move |_, cx| set(&sent, true, cx))
         .above(chips)
         .above(context_chips)
         .tool(AttachmentButton::new("chat-attach", move |paths, _, cx| {
@@ -195,7 +195,11 @@ fn levels() -> Vec<f32> {
         .collect()
 }
 
-pub fn pickers(window: &mut Window, cx: &mut App) -> impl IntoElement + use<> {
+pub fn pickers(
+    draft: &Entity<TextInput>,
+    window: &mut Window,
+    cx: &mut App,
+) -> impl IntoElement + use<> {
     let model = keep("chat-model", || SharedString::from("large"), window, cx);
     let mode = keep("chat-mode-pick", || SharedString::from("chat"), window, cx);
     let tools = keep("chat-tools", || (true, false, false), window, cx);
@@ -216,6 +220,13 @@ pub fn pickers(window: &mut Window, cx: &mut App) -> impl IntoElement + use<> {
             set(&tools, (web, code, images), cx)
         }
     };
+    let fill = |draft: &Entity<TextInput>, prompt: &'static str| {
+        let draft = draft.clone();
+        move |_: &mut Window, cx: &mut App| {
+            log::info!("gallery: prompt template");
+            draft.update(cx, |input, cx| input.set_text(prompt, cx))
+        }
+    };
     section(
         "ModelSelector / ModeSelector / ToolToggleMenu / PromptTemplateMenu",
         "The model is a forms::Select with a note on each; the mode a buttons::SegmentedControl; tools and saved prompts are menus::DropdownMenu, one with checks and one that inserts a prompt.",
@@ -255,12 +266,15 @@ pub fn pickers(window: &mut Window, cx: &mut App) -> impl IntoElement + use<> {
                     .item(MenuItem::check("Run code", code).on_click(flip(&tools, 1)))
                     .item(MenuItem::check("Make images", images).on_click(flip(&tools, 2))),
             ))
-            .child(DropdownMenu::new(
+            .child(probe(
                 "chat-templates",
-                "Prompts",
-                Menu::new()
-                    .item(MenuItem::new("Review this code").on_click(|_, _| log::info!("gallery: template review")))
-                    .item(MenuItem::new("Explain like a textbook").on_click(|_, _| log::info!("gallery: template explain"))),
+                DropdownMenu::new(
+                    "chat-templates",
+                    "Prompts",
+                    Menu::new()
+                        .item(MenuItem::new("Review this code").on_click(fill(draft, "Review the code below. List bugs first, then anything unclear, each with its line and a fix.")))
+                        .item(MenuItem::new("Explain like a textbook").on_click(fill(draft, "Explain the idea below to a newcomer: define terms before using them, one idea per paragraph."))),
+                ),
             )),
     )
 }
@@ -270,9 +284,10 @@ pub fn tuning(window: &mut Window, cx: &mut App) -> impl IntoElement + use<> {
     let (temperature, top_p, longest) = *values.read(cx);
     let system = window.use_keyed_state("chat-system", cx, |window, cx| {
         let mut input = TextInput::new(window, cx).multi_line(3, 8);
-        input.set_text("You answer about color in plain words. Cite sources.", cx);
+        input.set_text(SYSTEM, cx);
         input
     });
+    let reset = system.clone();
     let system_tokens = tokens(system.read(cx).text());
     let changed = values.clone();
     section(
@@ -303,7 +318,13 @@ pub fn tuning(window: &mut Window, cx: &mut App) -> impl IntoElement + use<> {
                     set(&changed, (t, p, l), cx)
                 },
             ))
-            .child(SystemPromptEditor::new("chat-system", &system, system_tokens, 400).on_reset(|_, _| log::info!("gallery: reset system prompt")))
+            .child(probe(
+                "chat-system",
+                div().w(px(560.)).child(
+                    SystemPromptEditor::new("chat-system", &system, system_tokens, 400)
+                        .on_reset(move |_, cx| reset.update(cx, |input, cx| input.set_text(SYSTEM, cx))),
+                ),
+            ))
             .child(
                 UsageBar::new(200_000.0)
                     .part("System", 1_200.0)

examples/gallery/pages/chat/mod.rs

@@ -38,11 +38,28 @@ const SCRIPT: &[Step] = &[
     Step::UpAt("chat-sources", 20.0, 10.0),
     Step::Wait(300),
     Step::Shot("sources"),
+    Step::DownAt("chat-templates", 30.0, 12.0),
+    Step::UpAt("chat-templates", 30.0, 12.0),
+    Step::Wait(200),
+    Step::Key("down"),
+    Step::Key("enter"),
+    Step::Wait(200),
+    Step::DownAt("chat-system", 160.0, 48.0),
+    Step::UpAt("chat-system", 160.0, 48.0),
+    Step::Key("cmd-a"),
+    Step::Type("Answer in one line."),
+    Step::Wait(200),
+    Step::Shot("prompts"),
+    Step::DownAt("chat-system", 548.0, 12.0),
+    Step::UpAt("chat-system", 548.0, 12.0),
+    Step::Wait(200),
+    Step::Shot("reset"),
     Step::DownAt("chat-sources", 20.0, 10.0),
     Step::UpAt("chat-sources", 20.0, 10.0),
 ];
 
 fn render(window: &mut Window, cx: &mut App) -> AnyElement {
+    let draft = compose::draft(window, cx);
     div()
         .child(talk::conversation(window, cx))
         .child(talk::streaming(window, cx))
@@ -54,8 +71,8 @@ fn render(window: &mut Window, cx: &mut App) -> AnyElement {
         .child(controls::thinking(window, cx))
         .child(cite::citations(window, cx))
         .child(cite::search(window, cx))
-        .child(compose::composer(window, cx))
-        .child(compose::pickers(window, cx))
+        .child(compose::composer(&draft, window, cx))
+        .child(compose::pickers(&draft, window, cx))
         .child(compose::tuning(window, cx))
         .into_any_element()
 }

src/chat/composer.rs

@@ -2,7 +2,7 @@ use std::{path::PathBuf, rc::Rc};
 
 use gpui::{
     AnyElement, App, ElementId, Entity, ExternalPaths, InteractiveElement, IntoElement,
-    ParentElement, PathPromptOptions, RenderOnce, SharedString, Styled, Window, div,
+    ParentElement, PathPromptOptions, RenderOnce, SharedString, Styled, Window, div, prelude::*,
 };
 use smallvec::SmallVec;
 
@@ -142,16 +142,17 @@ impl RenderOnce for InputHint {
     }
 }
 
-/// While files hover the composer, a veil over it that says a drop attaches them; `group` names the composer.
+/// While files hover its parent, a veil over it that says a drop attaches them; it takes the drop. The parent is `relative`.
 #[derive(IntoElement)]
 pub struct DragDropOverlay {
-    group: SharedString,
+    on_drop: OnPaths,
 }
 
 impl DragDropOverlay {
-    pub fn new(group: impl Into<SharedString>) -> Self {
+    /// `on_drop` gets the files dropped; a drop with a folder is refused.
+    pub fn new(on_drop: impl Fn(Vec<PathBuf>, &mut Window, &mut App) + 'static) -> Self {
         Self {
-            group: group.into(),
+            on_drop: Rc::new(on_drop),
         }
     }
 }
@@ -160,15 +161,24 @@ impl RenderOnce for DragDropOverlay {
     fn render(self, _: &mut Window, cx: &mut App) -> impl IntoElement {
         let theme = cx.theme();
         let colors = theme.colors.clone();
+        let take = self.on_drop;
         div()
             .absolute()
             .inset_0()
             .invisible()
-            .group_drag_over::<ExternalPaths>(self.group, |style| style.visible())
+            .drag_over::<ExternalPaths>(|style, _, _, _| style.visible())
+            .on_drop(
+                move |paths: &ExternalPaths, window, cx| match dropped(paths.paths(), true) {
+                    Ok(paths) => {
+                        log::info!("drag drop overlay: {} files dropped", paths.len());
+                        take(paths, window, cx)
+                    }
+                    Err(reason) => log::info!("drag drop overlay: refused a drop: {reason}"),
+                },
+            )
             .flex()
             .items_center()
             .justify_center()
-            .gap_2()
             .rounded(theme.radius(Radius::Xl))
             .border_1()
             .border_dashed()
@@ -177,11 +187,18 @@ impl RenderOnce for DragDropOverlay {
             .text_size(theme.text_size(TextSize::Sm))
             .text_color(colors.fg_muted)
             .child(
-                Icon::new(IconName::Upload)
-                    .size(IconSize::Sm)
-                    .color(colors.fg_muted),
+                div()
+                    .debug_selector(|| "drag-drop-overlay".into())
+                    .flex()
+                    .items_center()
+                    .gap_2()
+                    .child(
+                        Icon::new(IconName::Upload)
+                            .size(IconSize::Sm)
+                            .color(colors.fg_muted),
+                    )
+                    .child("Drop to attach"),
             )
-            .child("Drop to attach")
     }
 }
 
@@ -197,8 +214,8 @@ fn offers(
 ) -> Suggestions {
     let input = field.read(cx);
     let (text, caret) = (input.text().to_string(), input.cursor());
-    let active =
-        active_trigger(&text, caret, &['/', '@']).filter(|(at, mark)| *mark == '@' || *at == 0);
+    let active = active_trigger(&text, caret, &['/', '@'], |ch| !ch.is_whitespace())
+        .filter(|(at, mark)| *mark == '@' || *at == 0);
     let query = active.map_or(String::new(), |(at, mark)| {
         text[at + mark.len_utf8()..caret].to_lowercase()
     });
@@ -326,7 +343,6 @@ impl RenderOnce for PromptInput {
         let colors = theme.colors.clone();
         let ready = !self.field.read(cx).text().trim().is_empty();
         let focused = self.field.read(cx).focus().contains_focused(window, cx);
-        let group = SharedString::from(format!("composer-{}", self.id));
         let (send, enter) = (self.on_send.clone(), self.on_send.clone());
         let suggestions = offers(
             (self.id.clone(), "offers").into(),
@@ -347,7 +363,6 @@ impl RenderOnce for PromptInput {
         let busy = self.on_stop.is_some();
         let body = div()
             .id(self.id.clone())
-            .group(group.clone())
             .relative()
             .w_full()
             .flex()
@@ -388,19 +403,8 @@ impl RenderOnce for PromptInput {
                     .child(div().flex_1())
                     .child(button),
             );
-        match self.on_drop {
-            Some(take) => body
-                .on_drop(move |paths: &ExternalPaths, window, cx| {
-                    match dropped(paths.paths(), true) {
-                        Ok(paths) => {
-                            log::info!("composer: {} files dropped", paths.len());
-                            take(paths, window, cx)
-                        }
-                        Err(reason) => log::info!("composer: refused a drop: {reason}"),
-                    }
-                })
-                .child(DragDropOverlay::new(group)),
-            None => body,
-        }
+        body.when_some(self.on_drop, |body, take| {
+            body.child(DragDropOverlay { on_drop: take })
+        })
     }
 }

src/chat/params.rs

@@ -34,6 +34,15 @@ pub struct Parameter {
 
 type OnParameter = Rc<dyn Fn(&SharedString, f64, &mut Window, &mut App)>;
 
+/// Places that show the value, both ends and every step exactly.
+fn places(parameter: &Parameter) -> usize {
+    [parameter.value, parameter.min, parameter.max]
+        .into_iter()
+        .filter(|number| *number != 0.0)
+        .map(|number| decimals(number.abs()))
+        .fold(decimals(parameter.step), usize::max)
+}
+
 /// How answers are made, knob by knob: each a slider with its value, such as temperature, top p and the longest answer.
 #[derive(IntoElement)]
 pub struct ParameterPanel {
@@ -79,7 +88,7 @@ impl RenderOnce for ParameterPanel {
             .children(self.parameters.into_iter().map(|parameter| {
                 let change = self.on_change.clone();
                 let key = parameter.key.clone();
-                let places = decimals(parameter.step);
+                let places = places(&parameter);
                 div()
                     .flex()
                     .flex_col()
@@ -302,7 +311,7 @@ impl RenderOnce for SystemPromptEditor {
 
 #[cfg(test)]
 mod tests {
-    use super::cost;
+    use super::{Parameter, cost, places};
 
     #[test]
     fn cost_counts_tokens_at_their_prices() {
@@ -310,4 +319,38 @@ mod tests {
         assert_eq!(cost(2_000, 1_000, 3.0, 15.0), 0.021);
         assert_eq!(cost(0, 0, 3.0, 15.0), 0.0);
     }
+
+    #[test]
+    fn a_value_shows_the_places_of_its_step_and_range() {
+        let knob = |value, min, max, step| Parameter {
+            key: "k".into(),
+            label: "K".into(),
+            value,
+            min,
+            max,
+            step,
+            hint: None,
+        };
+        assert_eq!(
+            places(&knob(0.25, 0.25, 1.25, 0.5)),
+            2,
+            "the range starts off the step's grid"
+        );
+        assert_eq!(
+            places(&knob(1.0, 0.0, 1.25, 0.5)),
+            2,
+            "the top end needs two"
+        );
+        assert_eq!(places(&knob(0.7, 0.0, 2.0, 0.1)), 1);
+        assert_eq!(
+            places(&knob(-2.0, -2.0, 2.0, 1.0)),
+            0,
+            "whole numbers on both sides"
+        );
+        assert_eq!(
+            places(&knob(0.1 + 0.2, 0.0, 1.0, 0.1)),
+            1,
+            "float noise adds no places"
+        );
+    }
 }

src/chat/tests/compose.rs

@@ -1,19 +1,22 @@
 use gpui::{
-    AppContext as _, Context, Entity, Focusable, IntoElement, ParentElement, Render, SharedString,
-    Styled, TestAppContext, VisualTestContext, Window, div,
+    AppContext as _, Context, Entity, ExternalPaths, FileDropEvent, Focusable, IntoElement,
+    Modifiers, ParentElement, Render, SharedString, Styled, TestAppContext, VisualTestContext,
+    Window, div, point, px,
 };
 
 use super::settle;
 use crate::{
     chat::PromptInput,
     forms::{self, Choice, TextInput},
-    theme::Theme,
+    motion,
+    theme::{ActiveTheme, Theme},
 };
 
 /// A composer over a field, and what it asked: sends, commands and context.
 struct Compose {
     field: Entity<TextInput>,
     busy: bool,
+    commands: Vec<Choice>,
     sent: usize,
     picked: Vec<SharedString>,
 }
@@ -24,13 +27,13 @@ impl Render for Compose {
         let input = PromptInput::new("compose", &self.field, move |_, cx| {
             send.update(cx, |compose, _| compose.sent += 1)
         })
-        .commands(
-            [Choice::new("summarize", "/summarize")],
-            move |value, _, cx| command.update(cx, |compose, _| compose.picked.push(value.clone())),
-        )
+        .commands(self.commands.clone(), move |value, _, cx| {
+            command.update(cx, |compose, _| compose.picked.push(value.clone()))
+        })
         .context([Choice::new("lift", "lift.rs")], move |value, _, cx| {
             mention.update(cx, |compose, _| compose.picked.push(value.clone()))
-        });
+        })
+        .on_drop(|_, _, _| {});
         let input = if self.busy {
             input.busy(|_, _| {})
         } else {
@@ -40,14 +43,20 @@ impl Render for Compose {
     }
 }
 
-fn open(busy: bool, cx: &mut TestAppContext) -> (Entity<Compose>, &mut VisualTestContext) {
+fn open(
+    busy: bool,
+    commands: Vec<Choice>,
+    cx: &mut TestAppContext,
+) -> (Entity<Compose>, &mut VisualTestContext) {
     cx.update(|cx| {
         Theme::init(cx);
+        Theme::update(cx, |theme| theme.reduced_motion = true);
         forms::bind_keys(cx);
     });
     let (compose, cx) = cx.add_window_view(move |window, cx| Compose {
         field: cx.new(|cx| TextInput::new(window, cx).multi_line(1, 8)),
         busy,
+        commands,
         sent: 0,
         picked: Vec::new(),
     });
@@ -60,13 +69,44 @@ fn open(busy: bool, cx: &mut TestAppContext) -> (Entity<Compose>, &mut VisualTes
     (compose, cx)
 }
 
+fn summarize() -> Vec<Choice> {
+    vec![Choice::new("summarize", "/summarize")]
+}
+
+/// Commands `c00` to `c19`, some disabled.
+fn numbered(disabled: &[usize]) -> Vec<Choice> {
+    (0..20)
+        .map(|ix| {
+            let choice = Choice::new(format!("c{ix:02}"), format!("/c{ix:02}"));
+            if disabled.contains(&ix) {
+                choice.disabled()
+            } else {
+                choice
+            }
+        })
+        .collect()
+}
+
+/// Frames 2ms apart, past reduced motion's 1ms entrances.
+fn frames(cx: &mut VisualTestContext) {
+    for _ in 0..3 {
+        std::thread::sleep(std::time::Duration::from_millis(2));
+        cx.update(|window, _| window.refresh());
+        cx.run_until_parked();
+    }
+}
+
+fn picked(compose: &Entity<Compose>, cx: &mut VisualTestContext) -> Vec<SharedString> {
+    compose.read_with(cx, |compose, _| compose.picked.clone())
+}
+
 fn text(compose: &Entity<Compose>, cx: &mut VisualTestContext) -> String {
     cx.update(|_, cx| compose.read(cx).field.read(cx).text().to_string())
 }
 
 #[gpui::test]
 fn enter_sends_and_shift_enter_breaks_the_line(cx: &mut TestAppContext) {
-    let (compose, cx) = open(false, cx);
+    let (compose, cx) = open(false, summarize(), cx);
     cx.simulate_keystrokes("enter");
     assert_eq!(
         compose.read_with(cx, |compose, _| compose.sent),
@@ -90,7 +130,7 @@ fn enter_sends_and_shift_enter_breaks_the_line(cx: &mut TestAppContext) {
 
 #[gpui::test]
 fn a_slash_picks_a_command_and_an_at_sign_picks_context(cx: &mut TestAppContext) {
-    let (compose, cx) = open(false, cx);
+    let (compose, cx) = open(false, summarize(), cx);
     cx.simulate_input("/sum");
     settle(cx);
     cx.simulate_keystrokes("enter");
@@ -109,10 +149,90 @@ fn a_slash_picks_a_command_and_an_at_sign_picks_context(cx: &mut TestAppContext)
 
 #[gpui::test]
 fn a_busy_composer_holds_its_message(cx: &mut TestAppContext) {
-    let (compose, cx) = open(true, cx);
+    let (compose, cx) = open(true, summarize(), cx);
     cx.simulate_input("wait");
     settle(cx);
     cx.simulate_keystrokes("enter");
     assert_eq!(compose.read_with(cx, |compose, _| compose.sent), 0);
     assert_eq!(text(&compose, cx), "wait");
 }
+
+#[gpui::test]
+fn a_file_name_keeps_its_suggestions_past_a_dot(cx: &mut TestAppContext) {
+    let (compose, cx) = open(false, summarize(), cx);
+    cx.simulate_input("see @lift.");
+    settle(cx);
+    cx.simulate_keystrokes("enter");
+    settle(cx);
+    assert_eq!(text(&compose, cx), "see ");
+    assert_eq!(picked(&compose, cx), ["lift"]);
+    assert_eq!(compose.read_with(cx, |compose, _| compose.sent), 0);
+}
+
+#[gpui::test]
+fn arrows_pass_disabled_rows_and_keep_the_cursor_in_view(cx: &mut TestAppContext) {
+    let (compose, cx) = open(false, numbered(&[1]), cx);
+    cx.simulate_input("/");
+    frames(cx);
+    for _ in 0..16 {
+        cx.simulate_keystrokes("down");
+        frames(cx);
+    }
+    let (anchor, height) = cx.update(|window, cx| {
+        let anchor = compose.read(cx).field.read(cx).bounds_for(0);
+        let height = cx.theme().list_max_height().to_pixels(window.rem_size());
+        (anchor.expect("the slash is laid out"), height)
+    });
+    let foot = point(
+        anchor.left() + px(24.0),
+        anchor.bottom() + motion::NUDGE + height - px(8.0),
+    );
+    cx.simulate_mouse_move(foot, None, Modifiers::none());
+    cx.simulate_click(foot, Modifiers::none());
+    assert_eq!(
+        picked(&compose, cx),
+        ["c17"],
+        "sixteen steps past one disabled row land on the eighteenth, at the list's foot"
+    );
+}
+
+#[gpui::test]
+fn the_cursor_starts_on_the_first_enabled_row(cx: &mut TestAppContext) {
+    let (compose, cx) = open(false, numbered(&[0]), cx);
+    cx.simulate_input("/");
+    settle(cx);
+    cx.simulate_keystrokes("enter");
+    settle(cx);
+    assert_eq!(picked(&compose, cx), ["c01"]);
+}
+
+#[gpui::test]
+fn enter_on_only_disabled_rows_picks_and_sends_nothing(cx: &mut TestAppContext) {
+    let (compose, cx) = open(false, vec![Choice::new("c00", "/c00").disabled()], cx);
+    cx.simulate_input("/");
+    settle(cx);
+    cx.simulate_keystrokes("enter");
+    settle(cx);
+    assert_eq!(picked(&compose, cx), Vec::<SharedString>::new());
+    assert_eq!(compose.read_with(cx, |compose, _| compose.sent), 0);
+    assert_eq!(text(&compose, cx), "/");
+}
+
+#[gpui::test]
+fn files_over_the_composer_raise_the_veil(cx: &mut TestAppContext) {
+    let (_, cx) = open(false, summarize(), cx);
+    assert_eq!(
+        cx.debug_bounds("drag-drop-overlay"),
+        None,
+        "no veil at rest"
+    );
+    cx.simulate_event(FileDropEvent::Entered {
+        position: point(px(8.0), px(8.0)),
+        paths: ExternalPaths::default(),
+    });
+    settle(cx);
+    assert!(
+        cx.debug_bounds("drag-drop-overlay").is_some(),
+        "files over the composer raise the veil"
+    );
+}

src/documents/suggest.rs

@@ -3,7 +3,7 @@ use std::rc::Rc;
 use gpui::{App, ElementId, Entity, SharedString, Window};
 
 use crate::forms::{
-    Choice, Pick, Suggestions, TextInput, active_trigger, emoji_found, handles_matching,
+    Choice, Pick, Suggestions, TextInput, active_trigger, emoji_found, handles_matching, one_word,
     replace_trigger,
 };
 
@@ -36,7 +36,7 @@ pub(crate) fn offers(
     let (text, caret) = (input.text().to_string(), input.cursor());
     let mut marks = vec!['@', ':'];
     marks.extend(extra.as_ref().map(|(mark, _)| *mark));
-    let active = active_trigger(&text, caret, &marks);
+    let active = active_trigger(&text, caret, &marks, one_word);
     let query = active.map_or("", |(at, mark)| &text[at + mark.len_utf8()..caret]);
     let (rows, pick): (Vec<Choice>, Pick) = match active {
         Some((at, '@')) => {

src/forms/mention.rs

@@ -2,20 +2,30 @@ use std::{ops::Range, rc::Rc};
 
 use gpui::{
     App, Div, ElementId, Entity, InteractiveElement, IntoElement, ParentElement, RenderOnce,
-    SharedString, Stateful, Styled, Window, div, prelude::*,
+    ScrollHandle, SharedString, Stateful, Styled, Window, div, prelude::*,
 };
 
 use super::{
     Highlight, Input, TextInput,
-    options::{Choice, Pick, Popup},
+    options::{Choice, Pick, Popup, step},
     text::{Down, Enter, Up},
 };
 use crate::theme::ActiveTheme;
 
 const SHOWN: usize = 6;
 
-/// The trigger being typed: its byte offset and char, ending at `caret`.
-pub(crate) fn active_trigger(text: &str, caret: usize, triggers: &[char]) -> Option<(usize, char)> {
+/// A character of a one-word handle.
+pub(crate) fn one_word(ch: char) -> bool {
+    ch.is_alphanumeric() || ch == '_'
+}
+
+/// The trigger being typed, its query all `word` characters: its byte offset and char, ending at `caret`.
+pub(crate) fn active_trigger(
+    text: &str,
+    caret: usize,
+    triggers: &[char],
+    word: fn(char) -> bool,
+) -> Option<(usize, char)> {
     let before = &text[..caret];
     let (ix, ch) = before
         .char_indices()
@@ -26,10 +36,8 @@ pub(crate) fn active_trigger(text: &str, caret: usize, triggers: &[char]) -> Opt
         .chars()
         .next_back()
         .is_none_or(char::is_whitespace);
-    let word = before[ix + ch.len_utf8()..]
-        .chars()
-        .all(|ch| ch.is_alphanumeric() || ch == '_');
-    (opens && word).then_some((ix, ch))
+    let query = before[ix + ch.len_utf8()..].chars().all(word);
+    (opens && query).then_some((ix, ch))
 }
 
 /// Replaces the trigger and its query, `at..caret`, with `text`, as one undo step.
@@ -98,9 +106,28 @@ pub fn mention_highlights(text: &str, cx: &App) -> Vec<(Range<usize>, Highlight)
 struct Picking {
     highlighted: usize,
     dismissed: Option<usize>,
+    scroll: ScrollHandle,
 }
 
-/// Rows offered at a trigger in a field's text, and what a pick does: arrows choose, Enter or a press picks, Escape dismisses until the trigger ends.
+/// The row the cursor rests on: `at` kept in range and off disabled rows.
+fn usable(rows: &[Choice], at: usize) -> usize {
+    let at = at.min(rows.len().saturating_sub(1));
+    match rows.get(at) {
+        Some(row) if row.disabled => step(rows, at, 1),
+        _ => at,
+    }
+}
+
+/// Moves the cursor `by` rows past disabled ones and scrolls it into view.
+fn move_cursor(picking: &Entity<Picking>, rows: &[Choice], by: isize, cx: &mut App) {
+    picking.update(cx, |picking, cx| {
+        picking.highlighted = step(rows, picking.highlighted, by);
+        picking.scroll.scroll_to_item(picking.highlighted);
+        cx.notify();
+    });
+}
+
+/// Rows offered at a trigger in a field's text, and what a pick does: arrows choose past disabled rows, Enter or a press picks, Escape dismisses until the trigger ends.
 pub(crate) struct Suggestions {
     pub id: ElementId,
     pub state: Entity<TextInput>,
@@ -124,13 +151,20 @@ impl Suggestions {
         let open = focused
             && !self.rows.is_empty()
             && self.trigger.is_some_and(|ix| dismissed != Some(ix));
-        let count = self.rows.len();
-        let highlighted = picking.read(cx).highlighted.min(count.saturating_sub(1));
+        let rows: Rc<[Choice]> = self.rows.into();
+        let highlighted = usable(&rows, picking.read(cx).highlighted);
+        if highlighted != picking.read(cx).highlighted {
+            picking.update(cx, |picking, _| picking.highlighted = highlighted);
+        }
+        let scroll = picking.read(cx).scroll.clone();
         log::debug!(
-            "suggestions {:?}: open {open}, {count} rows, anchor {anchor:?}",
-            self.id
+            "suggestions {:?}: open {open}, {} rows, anchor {anchor:?}",
+            self.id,
+            rows.len()
         );
-        let (up, down, escape) = (picking.clone(), picking.clone(), picking);
+        let (up, down, chosen, escape) =
+            (picking.clone(), picking.clone(), picking.clone(), picking);
+        let (up_rows, down_rows, enter_rows) = (rows.clone(), rows.clone(), rows.clone());
         let (enter, trigger) = (self.pick.clone(), self.trigger);
         div()
             .id(self.id)
@@ -139,25 +173,24 @@ impl Suggestions {
             .capture_action(move |_: &Up, _, cx| {
                 if open {
                     cx.stop_propagation();
-                    up.update(cx, |picking, cx| {
-                        picking.highlighted = (picking.highlighted + count - 1) % count;
-                        cx.notify();
-                    });
+                    move_cursor(&up, &up_rows, -1, cx);
                 }
             })
             .capture_action(move |_: &Down, _, cx| {
                 if open {
                     cx.stop_propagation();
-                    down.update(cx, |picking, cx| {
-                        picking.highlighted = (picking.highlighted + 1) % count;
-                        cx.notify();
-                    });
+                    move_cursor(&down, &down_rows, 1, cx);
                 }
             })
             .capture_action(move |_: &Enter, window, cx| {
                 if open {
                     cx.stop_propagation();
-                    enter(highlighted, window, cx);
+                    let at = chosen.read(cx).highlighted;
+                    if enter_rows[at].disabled {
+                        log::info!("suggestions: enter on disabled row {at}");
+                    } else {
+                        enter(at, window, cx);
+                    }
                 }
             })
             .on_key_down(move |event, _, cx| {
@@ -175,12 +208,12 @@ impl Suggestions {
                     Popup {
                         id: "suggestions".into(),
                         anchor,
-                        rows: &self.rows,
+                        rows: &rows,
                         highlighted: Some(highlighted),
                         checked: None,
                         pick: self.pick,
                         dismiss: None,
-                        scroll: None,
+                        scroll: Some(&scroll),
                     }
                     .render(window, cx),
                 )
@@ -240,7 +273,7 @@ impl RenderOnce for MentionInput {
         let input = self.state.read(cx);
         let (text, caret) = (input.text().to_string(), input.cursor());
         let marks: Vec<char> = self.triggers.iter().map(|(trigger, _)| *trigger).collect();
-        let active = active_trigger(&text, caret, &marks);
+        let active = active_trigger(&text, caret, &marks, one_word);
         let matches: Vec<SharedString> = active
             .map(|(ix, trigger)| {
                 let names = &self
@@ -288,16 +321,20 @@ impl RenderOnce for MentionInput {
 
 #[cfg(test)]
 mod tests {
-    use super::{active_trigger, dismissal, mention_spans};
+    use super::{active_trigger, dismissal, mention_spans, one_word};
 
     #[test]
     fn triggers_open_after_space_and_close_on_space() {
         let marks = ['@', '#'];
-        assert_eq!(active_trigger("hi @ad", 6, &marks), Some((3, '@')));
-        assert_eq!(active_trigger("@", 1, &marks), Some((0, '@')));
-        assert_eq!(active_trigger("mail@ad", 7, &marks), None);
-        assert_eq!(active_trigger("hi @ada lovelace", 16, &marks), None);
-        assert_eq!(active_trigger("go #rel", 7, &marks), Some((3, '#')));
+        let at = |text: &str| active_trigger(text, text.len(), &marks, one_word);
+        assert_eq!(at("hi @ad"), Some((3, '@')));
+        assert_eq!(at("@"), Some((0, '@')));
+        assert_eq!(at("mail@ad"), None);
+        assert_eq!(at("hi @ada lovelace"), None);
+        assert_eq!(at("go #rel"), Some((3, '#')));
+        assert_eq!(at("see @lift."), None, "a handle is one word");
+        let file = active_trigger("see @lift.rs", 12, &marks, |ch| !ch.is_whitespace());
+        assert_eq!(file, Some((4, '@')), "a file name holds dots");
     }
 
     #[test]

src/forms/mod.rs

@@ -76,7 +76,9 @@ pub use knob::Knob;
 pub use listbox::ListBox;
 pub use masked::{COUNTRIES, MaskedInput, PhoneInput};
 pub use mention::{MentionInput, mention_highlights};
-pub(crate) use mention::{Suggestions, active_trigger, handles_matching, replace_trigger};
+pub(crate) use mention::{
+    Suggestions, active_trigger, handles_matching, one_word, replace_trigger,
+};
 pub use multi::MultiSelect;
 pub use number::{NumberInput, ScrubInput};
 pub use options::Choice;