windowManager: Update stacking during workspace switches

When animating workspace switches, windows on the old and new workspaces
are temporarily reparented. If windows are restacked, those windows will
thus be ignored by mutter until meta_switch_workspace_completed() resyncs
the stacking at the end of the animation.
As a result, activating a window on another workspace that is not on top
of the stack is very noticeably a two-step operation of switching workspace
and raising the window. There is a technical reason for that order[0], but
we can avoid the visible disruption by manually syncing the stack during
the switch operation.

[0] https://git.gnome.org/browse/mutter/tree/src/core/workspace.c#n590

https://bugzilla.gnome.org/show_bug.cgi?id=741680

diff --git a/js/ui/windowManager.js b/js/ui/windowManager.js
index d88c02242307fe981bc232b95789fcdbe36e3e7f..b8af0e0b6493c0af00a709169a3cb7cc4d1bd8f8 100644 (file)
--- a/js/ui/windowManager.js
+++ b/js/ui/windowManager.js
@@ -618,6 +618,7 @@ const WindowManager = new Lang.Class({
         this._shellwm.connect('destroy', Lang.bind(this, this._destroyWindow));
         this._shellwm.connect('filter-keybinding', Lang.bind(this, this._filterKeybinding));
         this._shellwm.connect('confirm-display-change', Lang.bind(this, this._confirmDisplayChange));
+        global.screen.connect('restacked', Lang.bind(this, this._syncStacking));
 
         this._workspaceSwitcherPopup = null;
         this._tilePreview = null;
@@ -1248,6 +1249,24 @@ const WindowManager = new Lang.Class({
         return !(this._allowedKeybindings[binding.get_name()] & Main.actionMode);
     },
 
+    _syncStacking: function() {
+        if (this._switchData == null)
+            return;
+
+        // Update stacking of windows in inGroup (aka the workspace we are
+        // switching to). Windows in outGroup are about to be hidden anyway,
+        // so we just ignore them here.
+        let windows = global.get_window_actors();
+        let sibling = null;
+        for (let i = 0; i < windows.length; i++) {
+            if (windows[i].get_parent() != this._switchData.inGroup)
+                continue;
+
+            this._switchData.inGroup.set_child_above_sibling(windows[i], sibling);
+            sibling = windows[i];
+        }
+    },
+
     _switchWorkspace : function(shellwm, from, to, direction) {
         if (!Main.sessionMode.hasWorkspaces || !this._shouldAnimate()) {
             shellwm.completed_switch_workspace();