Bug 52801 "Press F2 for focus" does not work for spell-checking hovers
"Press F2 for focus" does not work for spell-checking hovers.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
if (fPropertyChangeListener != null) {
			Preferences preferences= JavaCore.getPlugin().getPluginPreferences();
			preferences.removePropertyChangeListener(fPropertyChangeListener);
			fPropertyChangeListener= null;
		}
		
		if (fBracketMatcher != null) {
			fBracketMatcher.dispose();
			fBracketMatcher= null;
		}
		
		if (fSelectionHistory != null) {
			fSelectionHistory.dispose();
			fSelectionHistory= null;
		}
		
		if (fEditorSelectionChangedListener != null)  {
			fEditorSelectionChangedListener.uninstall(getSelectionProvider());
			fEditorSelectionChangedListener= null;
		}
				
		super.dispose();
	}
	
	protected void createActions() {
		super.createActions();
		
		ActionGroup oeg, ovg, jsg, sg;
		fActionGroups= new CompositeActionGroup(new ActionGroup[] {