Dimension () { // There is a bug in BasicComboPopup. It does not add renderer into CellRendererPane, // so font can be null here. Font oldFont = getFont(); if (oldFont == null) { setFont(UIUtil.getListFont()); } Dimension result = super.getPreferredSize(); if (oldFont == null) { setFont(null); } return UIUtil.updateListRowHeight(result); }