src/Tools/jEdit/src/isabelle_sidekick.scala

     data
   }
 
   class Keyword_Asset(keyword: String, text: String, range: Text.Range) extends IAsset
   {
-    private val css = GUI.imitate_font_css((new JLabel).getFont)
+    private val css = GUI.imitate_font_css(GUI.label_font())
 
     protected var _name = text
     protected var _start = int_to_pos(range.start)
     protected var _end = int_to_pos(range.stop)
     override def getIcon: Icon = null