Bug 33389 Read-Only files: Quick fix enabled and gets checkmark!
RC1 1. set a file to ready only. 2. Open the file an set the cursor inside 3. Open the 'Edit' menu. Note that 'Quick fix' is enabled, but 'Content assist' is not 4. Choose 'Quick fix' 5. Open the context menu: Quick fix got a checkmark!
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
if (fTabRatio == 0)
				return 0;
				
			int remainder= offsetInLine % fTabRatio;
			remainder= fTabRatio - remainder;
			for (int i= 0; i < remainder; i++)
				buffer.append(' ');
			return remainder;
		}
		
		public void customizeDocumentCommand(IDocument document, DocumentCommand command) {
			String text= command.text;
			if (text == null)
				return;
				
			int index= text.indexOf('\t');
			if (index > -1) {
				
				StringBuffer buffer= new StringBuffer();
				
				fLineTracker.set(command.text);
				int lines= fLineTracker.getNumberOfLines();
				
				try {
						
						for (int i= 0; i < lines; i++) {
							
							int offset= fLineTracker.getLineOffset(i);
							int endOffset= offset + fLineTracker.getLineLength(i);