Hello,
It can be done by creating the popup menu in a different way. This way works:
from javax.swing import JMenuItem
menu = system.gui.createPopupMenu([],[])
def delete():
print "done"
menuItem = JMenuItem("Delete",actionPerformed=delete)
menuItem.setFont(menuItem.getFont().deriveFont(80.0))
menu.add(menuItem)
menu.show(event)Best,