src/Tools/jEdit/src/completion_popup.scala

       val unicode = Isabelle_Encoding.is_active(buffer)
 
       def open_popup(result: Completion.Result): Unit = {
         val font =
           painter.getFont.deriveFont(
-            Font_Info.main_size(PIDE.options.real("jedit_popup_font_scale")))
+            Font_Info.main_size(scale = PIDE.options.real("jedit_popup_font_scale")))
 
         val range = result.range
 
         val loc1 = text_area.offsetToXY(range.start)
         if (loc1 != null) {