Bug 75711 AstProvider should not create AST if requested by SelectionListenerWithASTManager
3.1 M2 If SelectionListenerWithASTManager waits for an AST and the editor closes we should not create an AST for that one but return null instead.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
}
	/*
	 * @see org.eclipse.ui.texteditor.AbstractTextEditor#updatePropertyDependentActions()
	 */
	protected void updatePropertyDependentActions() {
		super.updatePropertyDependentActions();
		if (fEncodingSupport != null)
			fEncodingSupport.reset();
	}
	/*
	 * Update the hovering behavior depending on the preferences.
	 */
	private void updateHoverBehavior() {
		SourceViewerConfiguration configuration= getSourceViewerConfiguration();
		String[] types= configuration.getConfiguredContentTypes(getSourceViewer());
		for (int i= 0; i < types.length; i++) {
			
			String t= types[i];
			ISourceViewer sourceViewer= getSourceViewer();
			if (sourceViewer instanceof ITextViewerExtension2) {
							
				((ITextViewerExtension2)sourceViewer).removeTextHovers(t);
				
				int[] stateMasks= configuration.getConfiguredTextHoverStateMasks(getSourceViewer(), t);
				if (stateMasks != null) {
					for (int j= 0; j < stateMasks.length; j++)	{
						int stateMask= stateMasks[j];
						ITextHover textHover= configuration.getTextHover(sourceViewer, t, stateMask);
						((ITextViewerExtension2)sourceViewer).setTextHover(textHover, t, stateMask);
					}