void processHighlighter(@NotNull RangeHighlighterEx highlighter, boolean add) {
              HighlightInfo info = HighlightInfo.fromRangeHighlighter(highlighter);
              if (info != null && HighlightSeverity.ERROR.equals(info.getSeverity())) {
                int value = errors.addAndGet(add ? 1 : -1);
                if (value == 0 || value == 1) {
                  EdtInvocationManager.invokeLaterIfNeeded(() -> {
                    if (UIUtil.isShowing(myComboBox)) {
                      myComboBox.putClientProperty("JComponent.outline", value > 0 ? "error" : null);
                      myComboBox.repaint();
                    }
                  });
                }
              }
            }
void processHighlighter(@NotNull RangeHighlighterEx highlighter, boolean add)