Primitives · a raise keeps its state under its owner's id

A raise inside another was namespaced by its place in the layer's
queue, so one that came before it moved its id path and rebuilt its
keyed state and focus: an open date popup would lose its month when a
tip appeared. raise now takes its owner's id and draws under it, and
float and float_height pass the owner's id on from every call site.
A test holds a focused box in a raise while another comes before it.

src/forms/date/picker.rs

@@ -246,6 +246,7 @@ impl RenderOnce for DatePicker {
                 }
                 let (escape, done) = (close.clone(), close.clone());
                 float(
+                    id.clone(),
                     anchor,
                     CALENDAR_ROWS,
                     surface((id.clone(), "popup"), cx)
@@ -347,6 +348,7 @@ impl RenderOnce for DateRangePicker {
                 }
                 let (hover, pick, escape) = (state.clone(), state.clone(), close.clone());
                 float(
+                    id.clone(),
                     anchor,
                     CALENDAR_ROWS,
                     surface((id.clone(), "popup"), cx)