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 static char getPeerCharacter(char character) {
		switch (character) {
			case '(':
				return ')';
				
			case ')':
				return '(';
				
			case '<':
				return '>';
				
			case '>':
				return '<';
				
			case '[':
				return ']';
			case ']':
				return '[';
				
			case '"':
				return character;
				
			case '\'':
				return character;
			
			default:
				throw new IllegalArgumentException();
		}					
	}