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 askIfNonWorkbenchEncodingIsOk() {
		IDocumentProvider provider= getDocumentProvider();
		if (provider instanceof IStorageDocumentProvider) {
			IEditorInput input= getEditorInput();
			IStorageDocumentProvider storageProvider= (IStorageDocumentProvider)provider;
			String encoding= storageProvider.getEncoding(input);
			String defaultEncoding= storageProvider.getDefaultEncoding();
			if (encoding != null && !encoding.equals(defaultEncoding)) {
				Shell shell= getSite().getShell();
				String title= JavaEditorMessages.getString("CompilationUnitEditor.warning.save.nonWorkbenchEncoding.title"); 
				String msg;
				if (input != null)
					msg= MessageFormat.format(JavaEditorMessages.getString("CompilationUnitEditor.warning.save.nonWorkbenchEncoding.message1"), new String[] {input.getName(), encoding});
				else
					msg= MessageFormat.format(JavaEditorMessages.getString("CompilationUnitEditor.warning.save.nonWorkbenchEncoding.message2"), new String[] {encoding});
				return MessageDialog.openQuestion(shell, title, msg);
			}
		}
		return true;
	}
	
	public boolean isSaveAsAllowed() {
		return true;
	}
	
	/**
	 * The compilation unit editor implementation of this  <code>AbstractTextEditor</code>
	 * method asks the user for the workspace path of a file resource and saves the document
	 * there. See http://dev.eclipse.org/bugs/show_bug.cgi?id=6295
	 */