private @Nullable GrayFilter editGrayFilter(String key, String value) {
        String newValue = Messages.showInputDialog(getRootPane(),
                                                   IdeBundle.message(
                                                     "dialog.message.enter.new.value.for.0.in.form.brightness.contrast.alpha", key),
                                                   IdeBundle.message("dialog.title.gray.filter.editor"), null, value,
                                                   new InputValidator() {
                                                     @Override
                                                     public boolean checkInput(String inputString) {
                                                       return parseGrayFilter(inputString) != null;
                                                     }

                                                     @Override
                                                     public boolean canClose(String inputString) {
                                                       return checkInput(inputString);
                                                     }
                                                   });

        return newValue != null ? parseGrayFilter(newValue) : null;
      }
private @Nullable GrayFilter editGrayFilter(String key, String value)