protected void initPopupEditor(@NotNull EditorEx editor, Color background) {
    JLabel label = ExpandableSupport.createLabel(createCollapseExtension());
    label.setBorder(JBUI.Borders.empty(5, 3, 5, 7));
    editor.getContentComponent().putClientProperty(Expandable.class, this);
    editor.getScrollPane().setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
    editor.getScrollPane().setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    editor.getScrollPane().getVerticalScrollBar().setBackground(background);
    editor.getScrollPane().getVerticalScrollBar().add(JBScrollBar.LEADING, label);
    editor.getScrollPane().setViewportBorder(JBUI.Borders.empty(4, 6));
    label.setOpaque(true);
  }
protected void initPopupEditor(@NotNull EditorEx editor, Color background)