Bug 28698 Ctrl+O (show outline) does not work if the file being shown in the editor is read only
M4 The summary tells all. Works if the file is not read only. Is this by design?
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
}
		}
		private boolean hasIdentifierToTheLeft(IDocument document, int offset) {
			try {
				int start= offset;
				IRegion startLine= document.getLineInformationOfOffset(start);
				int minStart= startLine.getOffset();
				while (start != minStart && Character.isWhitespace(document.getChar(start - 1)))
					--start;
				
				return start != minStart && Character.isJavaIdentifierPart(document.getChar(start - 1));
			} catch (BadLocationException e) {
				return true;
			}			
		}
		private boolean hasCharacterToTheRight(IDocument document, int offset, char character) {
			try {
				int end= offset;
				IRegion endLine= document.getLineInformationOfOffset(end);
				int maxEnd= endLine.getOffset() + endLine.getLength();
				while (end != maxEnd && Character.isWhitespace(document.getChar(end)))
					++end;
				
				return end != maxEnd && document.getChar(end) == character;
			} catch (BadLocationException e) {
				
				return true;
			}			
		}