# HG changeset patch
# User Torsten <ttl@justmail.de>
# Date 1419425880 -3600
# Node ID 5e93d228ff6b3e3a9e636f2e56dbb7588195d1cd
# Parent  d93293218966f45b8fbeb294621e9a6c61c985a8
fix regression from 476032040df9 (endless loop while looking for active widget)

* main_window.cc (focus_changed): store start widget before looping through
  the focus change since previousInFocusChain does not return 0 at the
  beginning of the chain; moreover quit looking for active dock after 100 times

diff -r d93293218966 -r 5e93d228ff6b libgui/src/main-window.cc
--- a/libgui/src/main-window.cc	Tue Dec 23 16:29:02 2014 +0100
+++ b/libgui/src/main-window.cc	Wed Dec 24 13:58:00 2014 +0100
@@ -161,15 +161,24 @@
 
 // catch focus changes and determine the active dock widget
 void
-main_window::focus_changed (QWidget *, QWidget *w_new)
+main_window::focus_changed (QWidget *, QWidget *new_widget)
 {
   octave_dock_widget* dock = 0;
-  while (w_new && w_new != _main_tool_bar)
+  QWidget *w_new = new_widget;  // get a copy of new focus widget
+  QWidget *start = w_new;       // Save it as start of our search
+  int count = 0;                // fallback to prevent endless loop
+
+  while (w_new && w_new != _main_tool_bar && count < 100)
     {
       dock = qobject_cast <octave_dock_widget *> (w_new);
       if (dock)
-        break; // its a QDockWidget
+        break; // it is a QDockWidget ==> exit loop
+
       w_new = qobject_cast <QWidget *> (w_new->previousInFocusChain ());
+      if (w_new == start)
+        break; // we have arrived where we began ==> exit loop
+
+      count++;
     }
 
   // if new dock has focus, emit signal and store active focus