Index: trunk/src/org/openstreetmap/josm/gui/widgets/TextContextualPopupMenu.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/widgets/TextContextualPopupMenu.java	(revision 13503)
+++ trunk/src/org/openstreetmap/josm/gui/widgets/TextContextualPopupMenu.java	(revision 13504)
@@ -5,5 +5,4 @@
 
 import java.awt.GraphicsEnvironment;
-import java.awt.Toolkit;
 import java.awt.event.ActionEvent;
 import java.awt.event.KeyEvent;
@@ -23,4 +22,5 @@
 import javax.swing.undo.UndoManager;
 
+import org.openstreetmap.josm.Main;
 import org.openstreetmap.josm.spi.preferences.Config;
 import org.openstreetmap.josm.tools.ImageProvider;
@@ -86,7 +86,7 @@
                 if (!GraphicsEnvironment.isHeadless()) {
                     component.getInputMap().put(
-                            KeyStroke.getKeyStroke(KeyEvent.VK_Z, Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()), undoAction);
+                            KeyStroke.getKeyStroke(KeyEvent.VK_Z, Main.platform.getMenuShortcutKeyMaskEx()), undoAction);
                     component.getInputMap().put(
-                            KeyStroke.getKeyStroke(KeyEvent.VK_Y, Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()), redoAction);
+                            KeyStroke.getKeyStroke(KeyEvent.VK_Y, Main.platform.getMenuShortcutKeyMaskEx()), redoAction);
                 }
             }
Index: trunk/src/org/openstreetmap/josm/tools/PlatformHook.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/PlatformHook.java	(revision 13503)
+++ trunk/src/org/openstreetmap/josm/tools/PlatformHook.java	(revision 13504)
@@ -284,4 +284,5 @@
      */
     default int getMenuShortcutKeyMaskEx() {
+        // To remove when switching to Java 10+, and use Toolkit.getMenuShortcutKeyMaskEx instead
         return KeyEvent.CTRL_DOWN_MASK;
     }