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
if (!IDocument.DEFAULT_CONTENT_TYPE.equals(partition.getType()))
					return;
				
				if (!validateEditorInputState())
					return;
				
				final char character= event.character;
				final char closingCharacter= getPeerCharacter(character);
				final StringBuffer buffer= new StringBuffer();
				buffer.append(character);
				buffer.append(closingCharacter);
				
				document.replace(offset, length, buffer.toString());
				
				
				BracketLevel level= new BracketLevel();
				fBracketLevelStack.push(level);
				
				LinkedPositionGroup group= new LinkedPositionGroup(); 
				group.addPosition(new LinkedPosition(document, offset + 1, 0, LinkedPositionGroup.NO_STOP));
				
				LinkedModeModel model= new LinkedModeModel();
				model.addLinkingListener(this);
				model.addGroup(group);
				model.forceInstall();
				
				level.fOffset= offset;
				level.fLength= 2;