Bug 90528 Editor icon does not show problem decoration for second instance
3.1 M6 - open a .java file that has errors or warnings - the editor tab icon has the problem decoration - Window > New Window - open the same file in the new window - the editor tab icon is missing the problem decoration
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
private final String fCategory;
		/**
		 * Creates a new updater for the given <code>category</code>.
		 * 
		 * @param category the new category.
		 */
		public ExclusivePositionUpdater(String category) {
			fCategory= category;
		}
		/*
		 * @see org.eclipse.jface.text.IPositionUpdater#update(org.eclipse.jface.text.DocumentEvent)
		 */
		public void update(DocumentEvent event) {
			int eventOffset= event.getOffset();
			int eventOldLength= event.getLength();
			int eventNewLength= event.getText() == null ? 0 : event.getText().length();
			int deltaLength= eventNewLength - eventOldLength;
			try {
				Position[] positions= event.getDocument().getPositions(fCategory);
				for (int i= 0; i != positions.length; i++) {
					Position position= positions[i];
					if (position.isDeleted())