diff -r 9efdebe24c65 -r 0ffcad1f6130 src/Tools/jEdit/src-base/pide_docking_framework.scala
--- a/src/Tools/jEdit/src-base/pide_docking_framework.scala	Mon Mar 01 20:12:09 2021 +0100
+++ b/src/Tools/jEdit/src-base/pide_docking_framework.scala	Mon Mar 01 22:22:12 2021 +0100
@@ -60,7 +60,7 @@
       if (detach_operation.isDefined) {
         val detach_item = new JMenuItem("Detach")
         detach_item.addActionListener(new ActionListener {
-          def actionPerformed(evt: ActionEvent) { detach_operation.get.apply() }
+          def actionPerformed(evt: ActionEvent): Unit = detach_operation.get.apply()
         })
         menu.add(detach_item)
       }