quickshell: open tray menus at full size, not empty-then-grown

The DBus menu populates asynchronously and Steam's is slow, so the
panel was sized from an empty body: menuItems.width is fixed, making
the width final immediately while fullHeight was only padding. The
panel shot out sideways, then lurched taller when the items arrived —
two motions instead of one.

contextMenu now loads the menu first and opens once it has items,
falling back to a 500ms timeout so a menu that never populates cannot
strand the click. Hovering a tray icon also prefetches its menu, which
covers the wait in practice since you cannot click without hovering.

Clicking the open menu's own icon still closes it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

settings/quickshell.nix

@@ -1849,23 +1849,24 @@ in
                                     hoverEnabled: true
                                     acceptedButtons: Qt.NoButton
                                     onEntered: {
-                                        if (bar.activeDropdown) {
+                                        if (!modelData.hasMenu) return;
-                                            if (modelData.hasMenu && !(bar.activeDropdown === contextMenu && contextMenu.trayItem === modelData)) {
+                                        // Prefetch: you cannot click without
+                                        // hovering first, so start the DBus
+                                        // round-trip now and the menu is
+                                        // usually loaded before the click.
+                                        if (!bar.activeDropdown && menuOpener.menu !== modelData.menu) {
+                                            menuOpener.menu = modelData.menu;
+                                        }
+                                        if (!bar.activeDropdown) return;
+                                        if (bar.activeDropdown === contextMenu && contextMenu.trayItem === modelData) return;
+                                        let pos = parent.mapToItem(bar.contentItem, 0, parent.height / 2);
                                         if (bar.activeDropdown === contextMenu) {
                                             // Same dropdown, just switch content
-                                                    let pos = parent.mapToItem(bar.contentItem, 0, parent.height / 2);
                                             contextMenu.dropdownY = pos.y;
                                             contextMenu.trayItem = modelData;
                                             menuOpener.menu = modelData.menu;
                                         } else {
-                                                    bar.toggleDropdown(contextMenu, function() {
+                                            contextMenu.openFor(modelData, pos.y);
-                                                        let pos = parent.mapToItem(bar.contentItem, 0, parent.height / 2);
-                                                        contextMenu.dropdownY = pos.y;
-                                                        contextMenu.trayItem = modelData;
-                                                        menuOpener.menu = modelData.menu;
-                                                    });
-                                                }
-                                            }
                                         }
                                     }
                                 }
@@ -1873,15 +1874,14 @@ in
                                     anchors.fill: parent
                                     acceptedButtons: Qt.LeftButton | Qt.RightButton
                                     onClicked: (event) => {
-                                        if (modelData.hasMenu) {
+                                        if (!modelData.hasMenu) {
-                                            bar.toggleDropdown(contextMenu, function() {
-                                                let pos = parent.mapToItem(bar.contentItem, 0, parent.height / 2);
-                                                contextMenu.dropdownY = pos.y;
-                                                contextMenu.trayItem = modelData;
-                                                menuOpener.menu = modelData.menu;
-                                            });
-                                        } else {
                                             modelData.activate();
+                                        } else if (bar.activeDropdown === contextMenu && contextMenu.trayItem === modelData) {
+                                            // Clicking the open menu's own icon still closes it
+                                            contextMenu.animateClose();
+                                        } else {
+                                            let pos = parent.mapToItem(bar.contentItem, 0, parent.height / 2);
+                                            contextMenu.openFor(modelData, pos.y);
                                         }
                                     }
                                 }
@@ -2103,13 +2103,64 @@ in
                     fullHeight: menuItems.height + 2 * Theme.panelGap
 
                     onVisibleChanged: {
-                        if (!visible) menuOpener.menu = null;
+                        if (!visible) {
+                            menuOpener.menu = null;
+                            pendingItem = null;
+                            _menuWait.stop();
+                        }
                     }
 
                     QsMenuOpener {
                         id: menuOpener
                     }
 
+                    // The DBus menu populates asynchronously and Steam's is
+                    // slow. Opening on click sized the panel from an EMPTY
+                    // body: menuItems.width is fixed, so the width was already
+                    // final while fullHeight was just padding — the panel shot
+                    // out sideways, then lurched taller when the items landed.
+                    // Two motions instead of one. Load first, open once there
+                    // is something to show.
+                    property var pendingItem: null
+                    readonly property bool menuReady:
+                        menuOpener.children && menuOpener.children.values.length > 0
+
+                    function openFor(item, y) {
+                        dropdownY = y;
+                        trayItem = item;
+                        menuOpener.menu = item.menu;
+                        if (menuReady) {
+                            pendingItem = null;
+                            bar.toggleDropdown(contextMenu, null);
+                        } else {
+                            pendingItem = item;
+                            _menuWait.restart();
+                        }
+                    }
+
+                    function openPending() {
+                        if (!pendingItem) return;
+                        pendingItem = null;
+                        _menuWait.stop();
+                        if (bar.activeDropdown !== contextMenu)
+                            bar.toggleDropdown(contextMenu, null);
+                    }
+
+                    // Never strand a click if the menu never populates.
+                    Timer {
+                        id: _menuWait
+                        interval: 500
+                        onTriggered: contextMenu.openPending()
+                    }
+
+                    Connections {
+                        target: menuOpener.children
+                        function onValuesChanged() {
+                            if (contextMenu.pendingItem && contextMenu.menuReady)
+                                contextMenu.openPending();
+                        }
+                    }
+
                     Card {
                         id: menuItems
                         anchors.centerIn: parent