Bug 53473 [EditorMgmt] Leak editor++ on open/close
Build I20040226 1. Create a simple project P; create a file file.txt. 2. Open file.txt; close file.txt Using a profiler, check if there are any instances hanging around. I discover a left-over editor. In addition, I leak many ActionHandler and HandlerSubmissions (equal number). (I appear to leak 1 additional editor and N ActionHandler and HandlerSubmission instances for each pair of open/close operations) (I can also cause this with the java editor)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/ASTProvider.java
*/
	private CompilationUnit createAST(IJavaElement je, IProgressMonitor progressMonitor) {
		ASTParser parser = ASTParser.newParser(AST.LEVEL_2_0);
		parser.setResolveBindings(true);
		
		if (je.getElementType() == IJavaElement.COMPILATION_UNIT)
			parser.setSource((ICompilationUnit)je);
		else if (je.getElementType() == IJavaElement.CLASS_FILE)
			parser.setSource((IClassFile)je);
		
		if (progressMonitor != null && progressMonitor.isCanceled())
			return null;
		try {
			return (CompilationUnit)parser.createAST(progressMonitor);
		} catch (IllegalStateException ex) {
			return null;
		}
	}
	
	/**
	 * Dispose this AST provider.
	 */
	public void dispose() {
		
		fWorkbench.removeWindowListener(fActivationListener);
		fActivationListener= null;
		
		disposeAST();
		
		synchronized (fWaitLock) {