Fix pointer navigation in Quattro launcher menus (#6343)

Accumulate sub-threshold movement so slow motion with a flat acceleration profile updates selection. Sample pointer state on row entry and carry pointer intent through subordinate menus while preserving predictable keyboard selection.

shell/Ui/PointerMoveGate.qml

@@ -2,22 +2,31 @@ import QtQuick
 
 // Filters synthetic hover churn from moving delegates under a stationary
 // pointer. Call reset() after keyboard/list mutations, then moved() from a
-// row MouseArea's onPositionChanged before changing cursor selection.
+// row MouseArea's onPositionChanged before changing cursor selection. A
+// transition known to originate from the pointer can call allowInitialSample()
+// so the item under the stationary pointer remains selected.
 QtObject {
   id: root
 
   property Item referenceItem: null
   property real threshold: 1
   property bool primed: false
+  property bool initialSampleAllowed: false
   property real lastX: 0
   property real lastY: 0
 
   function reset() {
     root.primed = false
+    root.initialSampleAllowed = false
     root.lastX = 0
     root.lastY = 0
   }
 
+  function allowInitialSample() {
+    root.reset()
+    root.initialSampleAllowed = true
+  }
+
   function moved(item, mouse) {
     if (!item || !mouse) {
       root.reset()
@@ -26,12 +35,19 @@ QtObject {
 
     var target = root.referenceItem || item
     var point = item.mapToItem(target, mouse.x, mouse.y)
-    var didMove = root.primed
-      && (Math.abs(point.x - root.lastX) > root.threshold || Math.abs(point.y - root.lastY) > root.threshold)
+    var firstSample = !root.primed
+    var didMove = !firstSample
+      ? Math.abs(point.x - root.lastX) > root.threshold || Math.abs(point.y - root.lastY) > root.threshold
+      : root.initialSampleAllowed
 
-    root.lastX = point.x
-    root.lastY = point.y
+    // Keep the previous accepted position while filtering jitter so slow,
+    // sub-threshold steps accumulate into deliberate pointer movement.
+    if (firstSample || didMove) {
+      root.lastX = point.x
+      root.lastY = point.y
+    }
     root.primed = true
+    root.initialSampleAllowed = false
 
     return didMove
   }

shell/plugins/launcher/Launcher.qml

@@ -74,11 +74,11 @@ Item {
       ? root.contentMargin * 2 + root.searchHeight + root.contentSpacing + requestedListHeight
       : 400
 
-    root.opened = true
     root.filterText = payload.query || ""
     root.selectedIndex = 0
     root.cursorActive = true
     root.disarmHover()
+    root.opened = true
     root.rebuildDisplay()
     // The shell may start before first-install packages have finished placing
     // their icons. Refresh here even when the desktop entry list did not change.
@@ -626,9 +626,14 @@ Item {
               }
 
               MouseArea {
+                id: mouseArea
                 anchors.fill: parent
                 hoverEnabled: true
                 cursorShape: Qt.PointingHandCursor
+                onEntered: root.selectFromPointer(row.index, row, {
+                  x: mouseArea.mouseX,
+                  y: mouseArea.mouseY
+                })
                 onPositionChanged: function(mouse) {
                   root.selectFromPointer(row.index, row, mouse)
                 }

shell/plugins/menu/Menu.qml

@@ -520,14 +520,15 @@ Item {
     root.rebuildDisplay()
   }
 
-  function setActiveMenu(id, pushHistory) {
+  function setActiveMenu(id, pushHistory, fromPointer) {
     if (!root.item(id)) id = "root"
     if (pushHistory && id !== root.activeMenu) root.navStack = root.navStack.concat([root.activeMenu])
     root.activeMenu = id
     root.filterText = ""
     root.selectedIndex = 0
     root.cursorActive = true
-    root.disarmPointer()
+    if (fromPointer) pointerGate.allowInitialSample()
+    else root.disarmPointer()
     root.rebuildDisplay()
     root.loadProviderForMenu(id)
   }
@@ -547,7 +548,7 @@ Item {
     return true
   }
 
-  function activateIndex(index) {
+  function activateIndex(index, fromPointer) {
     if (root.dmenuActive) {
       if (root.mode === "input") {
         root.applyDmenuSelection(root.filterText)
@@ -562,7 +563,7 @@ Item {
 
     var row = displayModel.get(index)
     if (row.kind === "menu" || row.kind === "link") {
-      root.setActiveMenu(row.target || row.itemId, true)
+      root.setActiveMenu(row.target || row.itemId, true, fromPointer)
     } else {
       root.applySelected(row.itemId, row.action)
     }
@@ -1043,13 +1044,17 @@ Item {
                 anchors.fill: parent
                 hoverEnabled: true
                 cursorShape: Qt.PointingHandCursor
+                onEntered: root.selectFromPointer(row.index, row, {
+                  x: mouseArea.mouseX,
+                  y: mouseArea.mouseY
+                })
                 onPositionChanged: function(mouse) {
                   root.selectFromPointer(row.index, row, mouse)
                 }
                 onClicked: {
                   root.cursorActive = true
                   root.selectedIndex = row.index
-                  root.activateIndex(row.index)
+                  root.activateIndex(row.index, true)
                 }
               }
             }