Merge lp:~mterry/unity-greeter/focus-main-window-on-unmap into lp:unity-greeter

[Michael Terry]

Currently, if you open a dialog like the Switch Off one, then close it, you lose the focus-styling around the user list's entry box (though keyboard presses still go to it).

Calling main_window.get_window ().focus () after an UnmapEvent fixes it (just as if main_window received a MapEvent).

But how to tell when to do that? After every Unmap seems extreme. And ideally we'd only do it in cases where the user list is receiving keyboard presses but not focused (this weird halfway-focus GTK is giving us). As far as GTK/GDK/X are concerned, the window doesn't seem to have the focus in that state.

The closest I came is asking X directly, what has the focus. In this state, it gives back an odd pointer value like 0xaf and a revert_to value of X.RevertTo.None. So I'm using the revert_to value as a key that no other window has a claim to the focus.

This branch seems to work for me, but it feels a little black magicky.

=== modified file 'src/unity-greeter.vala'
--- src/unity-greeter.vala	2012-09-04 14:45:06 +0000
+++ src/unity-greeter.vala	2012-09-15 03:30:25 +0000
@@ -262,7 +262,7 @@
         var xevent = (X.Event*)gxevent;
         if (xevent.type == X.EventType.MapNotify)
         {
-            var display = Gdk.Display.get_default ();
+            var display = Gdk.x11_lookup_xdisplay (xevent.xmap.display);
             var xwin = xevent.xmap.window;
             var win = Gdk.X11Window.foreign_new_for_display (display, xwin);
 
@@ -280,6 +280,29 @@
                     main_window.menubar.keyboard_window.get_window ().raise ();
             }
         }
+        else if (xevent.type == X.EventType.UnmapNotify)
+        {
+            // Since we aren't keeping track of focus (for example, we don't
+            // track the Z stack of windows) like a normal WM would, when we
+            // decide here where to return focus after another window unmaps,
+            // we don't have much to go on.  X will tell us if we should take
+            // focus back.  (I could not find an obvious way to determine this,
+            // but checking if the X input focus is RevertTo.None seems
+            // reliable.)
+
+            X.Window xwin;
+            int revert_to;
+            xevent.xunmap.display.get_input_focus (out xwin, out revert_to);
+
+            if (revert_to == X.RevertTo.None)
+            {
+                main_window.get_window ().focus (Gdk.CURRENT_TIME);
+
+                /* Make sure to keep keyboard above */
+                if (main_window.menubar.keyboard_window != null)
+                    main_window.menubar.keyboard_window.get_window ().raise ();
+            }
+        }
         return Gdk.FilterReturn.CONTINUE;
     }