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
private boolean isTabConversionEnabled() {
		IPreferenceStore store= getPreferenceStore();
		return store.getBoolean(SPACES_FOR_TABS);
	}
	
	public void dispose() {
		ISourceViewer sourceViewer= getSourceViewer();
		if (sourceViewer instanceof ITextViewerExtension)
			((ITextViewerExtension) sourceViewer).removeVerifyKeyListener(fBracketInserter);
		if (fJavaEditorErrorTickUpdater != null) {
			fJavaEditorErrorTickUpdater.dispose();
			fJavaEditorErrorTickUpdater= null;
		}
		
		if (fActionGroups != null) {
			fActionGroups.dispose();
			fActionGroups= null;
		}
			
		super.dispose();
	}
	
	/*
	 * @see AbstractTextEditor#createPartControl(Composite)
	 */
	public void createPartControl(Composite parent) {
		
		super.createPartControl(parent);