FWD » Core Development » User Interface

This can be reproduced in current trunk.

1. Open COMBO-BOX drop down by clicking into the widget.
2. Press Alt-tab.
3. An NPE is thrown, see below for the call stack.

Thread [main] (Suspended (exception NullPointerException))    
    ThinClient.invokeTriggers(Widget, Widget, long, int, boolean, Integer, Integer) line: 16770    
    ThinClient.invokeTriggers(Widget, Widget, int, boolean) line: 16639    
    ThinClient.processProgressEvent(Event) line: 16217    
    FocusManager.focusChange(Widget, boolean, boolean) line: 1388    
    ThinClient.nextTabStop(Widget) line: 18350    
    ComboBoxGuiImpl(ComboBox<O>).processKeyEvent(KeyInput) line: 505    
    ComboBoxGuiImpl.processKeyEvent(KeyInput) line: 494    
    ComboBox$1.run() line: 1369    
    ThinClient.eventBracket(boolean, Runnable) line: 14272    
    ThinClient.eventDrawingBracket(Widget<?>, boolean, boolean, Runnable) line: 14213    
    ThinClient.independentEventDrawingBracket(Widget, Runnable) line: 14086    
    ComboBoxGuiImpl(ComboBox<O>).processSystemKey(KeyInput) line: 1364    
    ComboBoxGuiImpl.processFocusMoveKey(KeyInput) line: 660    
    ComboBoxGuiImpl.postprocessDropDown() line: 940    
    ComboBoxGuiImpl(ComboBox<O>).activate() line: 1153    

The cause seems to be in FocusManager. It must be made aware of the overlay windows when calculating the next focused widget on TAB.

Cannot reproduce anymore, resolved by #3062.