Re: [albireo-dev] Traversing out of embedded SwingControls on Windows

[Gordon Hirsch <gordon.hirsch@xxxxxxx>]

Gordon Hirsch wrote:
> I'm discovering
> that Windows does not report the current focus state reliably when there
> are embedded AWT frames in the focus cycle.

This problem affects some of the code from my initial commit as well (in 
particular, the code handling this test case: 
http://wiki.eclipse.org/Albireo_Focus_Management_Test_Cases#Keep_focus_when_clicking_on_parent_view_tab).

I was relying on the accuracy of Display.getFocusControl to decide 
whether to manually reactivate the SwingControl.

The original code also had a bug in that it did not check whether 
another window altogether had taken the focus before manually reactivating.






### Eclipse Workspace Patch 1.0
#P org.eclipse.albireo.core
Index: src/org/eclipse/albireo/internal/FocusHandler.java
===================================================================
RCS file: /cvsroot/technology/org.eclipse.albireo/org.eclipse.albireo.core/src/org/eclipse/albireo/internal/FocusHandler.java,v
retrieving revision 1.9
diff -u -r1.9 FocusHandler.java
--- src/org/eclipse/albireo/internal/FocusHandler.java	21 Feb 2008 21:18:55 -0000	1.9
+++ src/org/eclipse/albireo/internal/FocusHandler.java	22 Feb 2008 04:13:35 -0000
@@ -243,10 +243,22 @@
         if (!display.isDisposed()) {
             ThreadingHandler.getInstance().asyncExec(display, new Runnable() {
                 public void run() {
-                    if (!display.isDisposed() && (swingControl == display.getFocusControl())) {
+                    if (!swingControl.isDisposed() &&
+                            
+                        // Make sure that this control is in the active shell, so focus is not stolen from other windows    
+                        (display.getActiveShell() == swingControl.getShell()) && 
+                        
+                        // Check that this control still the focus control, despite the recent deactivation.
+                        // BUT... Display.getFocusControl is unreliable when another embedded AWT window has 
+                        // become active, so to be safe, make sure that no other Swing control has been activated
+                        // (otherwise we will steal focus from some other active SwingControl)
+                        (swingControl == display.getFocusControl() && (activeSwingControl == null))) {
+                        
                         if (verboseFocusEvents) {
                             trace("Manually reactivating " + swingControl);
                         }
+                        // Ideally, we would directly activate SwingControl here, but there seems to be 
+                        // no way to do that, so activate the underlying AWT embedded frame
                         synthesizeWindowActivation(true);
                     }
                 }
@@ -325,7 +337,7 @@
     // ========== Listener implementations
     
     protected class SwtEventFilter implements Listener {
-
+        
         public void handleEvent(Event event) {
             if (event.widget != swingControl) {
                 return;