Bug 63898 [reconciling] Multiple threads calling IJavaReconcilingListener#reconciled() at the same time
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
private RememberedOffset fStartOffset= new RememberedOffset();
		
		private RememberedOffset fEndOffset= new RememberedOffset();
		/**
		 * Remember current selection.
		 */
		public void remember() {
			/* https://bugs.eclipse.org/bugs/show_bug.cgi?id=52257
			 * This method may be called inside an async call posted
			 * to the UI thread, so protect against intermediate disposal
			 * of the editor.
			 */
			ISourceViewer viewer= getSourceViewer();
			if (viewer != null) {
				IRegion selection= getSignedSelection(viewer);
				int startOffset= selection.getOffset();