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 AbstractTextEditor#adjustHighlightRange(int, int)
	 */
	protected void adjustHighlightRange(int offset, int length) {
		
		try {
			
			IJavaElement element= getElementAt(offset);
			while (element instanceof ISourceReference) {
				ISourceRange range= ((ISourceReference) element).getSourceRange();
				if (offset < range.getOffset() + range.getLength() && range.getOffset() < offset + length) {
					
					ISourceViewer viewer= getSourceViewer();
					if (viewer instanceof ITextViewerExtension5) {
						ITextViewerExtension5 extension= (ITextViewerExtension5) viewer;
						extension.exposeModelRange(new Region(range.getOffset(), range.getLength()));
					}
					
					setHighlightRange(range.getOffset(), range.getLength(), true);
					if (fOutlinePage != null) {
						fOutlineSelectionChangedListener.uninstall(fOutlinePage);
						fOutlinePage.select((ISourceReference) element);
						fOutlineSelectionChangedListener.install(fOutlinePage);
					}
					
					return;
				}
				element= element.getParent();
			}