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
}
	
	protected void setSelection(ISourceReference reference, boolean moveCursor) {
		if (getSelectionProvider() == null)
			return;
		ISelection selection= getSelectionProvider().getSelection();
		if (selection instanceof TextSelection) {
			TextSelection textSelection= (TextSelection) selection;
			
			
			
			if (moveCursor && (textSelection.getOffset() != 0 || textSelection.getLength() != 0))
				markInNavigationHistory();
		}
		
		if (reference != null) {
			
			StyledText  textWidget= null;
			
			ISourceViewer sourceViewer= getSourceViewer();
			if (sourceViewer != null)
				textWidget= sourceViewer.getTextWidget();
			
			if (textWidget == null)
				return;
				
			try {
				ISourceRange range= null;
				if (reference instanceof ILocalVariable) {
					IJavaElement je= ((ILocalVariable)reference).getParent();