Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/LayerListDialog.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/LayerListDialog.java	(revision 12747)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/LayerListDialog.java	(revision 12748)
@@ -67,5 +67,4 @@
 import org.openstreetmap.josm.gui.layer.MainLayerManager.ActiveLayerChangeListener;
 import org.openstreetmap.josm.gui.layer.NativeScaleLayer;
-import org.openstreetmap.josm.gui.util.GuiHelper;
 import org.openstreetmap.josm.gui.widgets.DisableShortcutsOnFocusGainedTextField;
 import org.openstreetmap.josm.gui.widgets.JosmTextField;
@@ -216,6 +215,6 @@
         // Disable some default JTable shortcuts to use JOSM ones (see #5678, #10458)
         for (KeyStroke ks : new KeyStroke[] {
-                KeyStroke.getKeyStroke(KeyEvent.VK_C, GuiHelper.getMenuShortcutKeyMaskEx()),
-                KeyStroke.getKeyStroke(KeyEvent.VK_V, GuiHelper.getMenuShortcutKeyMaskEx()),
+                KeyStroke.getKeyStroke(KeyEvent.VK_C, Main.platform.getMenuShortcutKeyMaskEx()),
+                KeyStroke.getKeyStroke(KeyEvent.VK_V, Main.platform.getMenuShortcutKeyMaskEx()),
                 KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, InputEvent.SHIFT_DOWN_MASK),
                 KeyStroke.getKeyStroke(KeyEvent.VK_UP, InputEvent.SHIFT_DOWN_MASK),
Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java	(revision 12747)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java	(revision 12748)
@@ -50,5 +50,4 @@
 import org.openstreetmap.josm.data.osm.event.DatasetEventManager;
 import org.openstreetmap.josm.data.osm.event.DatasetEventManager.FireMode;
-import org.openstreetmap.josm.data.osm.search.SearchCompiler;
 import org.openstreetmap.josm.data.osm.event.NodeMovedEvent;
 import org.openstreetmap.josm.data.osm.event.PrimitivesAddedEvent;
@@ -57,4 +56,5 @@
 import org.openstreetmap.josm.data.osm.event.TagsChangedEvent;
 import org.openstreetmap.josm.data.osm.event.WayNodesChangedEvent;
+import org.openstreetmap.josm.data.osm.search.SearchCompiler;
 import org.openstreetmap.josm.gui.MainApplication;
 import org.openstreetmap.josm.gui.MapView;
@@ -72,5 +72,4 @@
 import org.openstreetmap.josm.gui.layer.MainLayerManager.ActiveLayerChangeListener;
 import org.openstreetmap.josm.gui.layer.OsmDataLayer;
-import org.openstreetmap.josm.gui.util.GuiHelper;
 import org.openstreetmap.josm.gui.util.HighlightHelper;
 import org.openstreetmap.josm.gui.widgets.CompileSearchTextDecorator;
@@ -183,5 +182,5 @@
         // Do not hide copy action because of default JList override (fix #9815)
         displaylist.getActionMap().put("copy", MainApplication.getMenu().copy);
-        displaylist.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_C, GuiHelper.getMenuShortcutKeyMaskEx()), "copy");
+        displaylist.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_C, Main.platform.getMenuShortcutKeyMaskEx()), "copy");
 
         updateActionsRelationLists();
Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/properties/TagEditHelper.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/properties/TagEditHelper.java	(revision 12747)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/properties/TagEditHelper.java	(revision 12748)
@@ -69,7 +69,7 @@
 import org.openstreetmap.josm.data.osm.OsmPrimitive;
 import org.openstreetmap.josm.data.osm.Tag;
+import org.openstreetmap.josm.data.osm.search.SearchCompiler;
 import org.openstreetmap.josm.data.osm.search.SearchParseError;
 import org.openstreetmap.josm.data.osm.search.SearchSetting;
-import org.openstreetmap.josm.data.osm.search.SearchCompiler;
 import org.openstreetmap.josm.data.preferences.BooleanProperty;
 import org.openstreetmap.josm.data.preferences.CollectionProperty;
@@ -810,5 +810,5 @@
         @Override
         public void setContentPane(Container contentPane) {
-            final int commandDownMask = GuiHelper.getMenuShortcutKeyMaskEx();
+            final int commandDownMask = Main.platform.getMenuShortcutKeyMaskEx();
             List<String> lines = new ArrayList<>();
             Shortcut.findShortcut(KeyEvent.VK_1, commandDownMask).ifPresent(sc ->
Index: /trunk/src/org/openstreetmap/josm/gui/util/GuiHelper.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/util/GuiHelper.java	(revision 12747)
+++ /trunk/src/org/openstreetmap/josm/gui/util/GuiHelper.java	(revision 12748)
@@ -66,4 +66,5 @@
 import org.openstreetmap.josm.tools.LanguageInfo;
 import org.openstreetmap.josm.tools.Logging;
+import org.openstreetmap.josm.tools.PlatformHook;
 import org.openstreetmap.josm.tools.bugreport.BugReport;
 import org.openstreetmap.josm.tools.bugreport.ReportedException;
@@ -470,5 +471,7 @@
      * @return extended modifier key used as the appropriate accelerator key for menu shortcuts
      * @since 7539
-     */
+     * @deprecated to be removed end of 2017. Use {@link PlatformHook#getMenuShortcutKeyMaskEx()} instead
+     */
+    @Deprecated
     public static int getMenuShortcutKeyMaskEx() {
         return Main.isPlatformOsx() ? KeyEvent.META_DOWN_MASK : KeyEvent.CTRL_DOWN_MASK;
Index: /trunk/src/org/openstreetmap/josm/tools/PlatformHook.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/PlatformHook.java	(revision 12747)
+++ /trunk/src/org/openstreetmap/josm/tools/PlatformHook.java	(revision 12748)
@@ -3,4 +3,6 @@
 
 import java.awt.GraphicsEnvironment;
+import java.awt.Toolkit;
+import java.awt.event.KeyEvent;
 import java.io.BufferedReader;
 import java.io.File;
@@ -242,4 +244,19 @@
 
     /**
+     * Returns extended modifier key used as the appropriate accelerator key for menu shortcuts.
+     * It is advised everywhere to use {@link Toolkit#getMenuShortcutKeyMask()} to get the cross-platform modifier, but:
+     * <ul>
+     * <li>it returns KeyEvent.CTRL_MASK instead of KeyEvent.CTRL_DOWN_MASK. We used the extended
+     *    modifier for years, and Oracle recommends to use it instead, so it's best to keep it</li>
+     * <li>the method throws a HeadlessException ! So we would need to handle it for unit tests anyway</li>
+     * </ul>
+     * @return extended modifier key used as the appropriate accelerator key for menu shortcuts
+     * @since 12748 (as a replacement to {@code GuiHelper.getMenuShortcutKeyMaskEx()})
+     */
+    default int getMenuShortcutKeyMaskEx() {
+        return KeyEvent.CTRL_DOWN_MASK;
+    }
+
+    /**
      * Called when an outdated version of Java is detected at startup.
      * @since 12270
Index: /trunk/src/org/openstreetmap/josm/tools/PlatformHookOsx.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/PlatformHookOsx.java	(revision 12747)
+++ /trunk/src/org/openstreetmap/josm/tools/PlatformHookOsx.java	(revision 12748)
@@ -76,4 +76,9 @@
         }
         checkExpiredJava(callback);
+    }
+
+    @Override
+    public int getMenuShortcutKeyMaskEx() {
+        return KeyEvent.META_DOWN_MASK;
     }
 
Index: /trunk/src/org/openstreetmap/josm/tools/Shortcut.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/Shortcut.java	(revision 12747)
+++ /trunk/src/org/openstreetmap/josm/tools/Shortcut.java	(revision 12748)
@@ -23,5 +23,4 @@
 
 import org.openstreetmap.josm.Main;
-import org.openstreetmap.josm.gui.util.GuiHelper;
 
 /**
@@ -370,5 +369,5 @@
         if (initdone) return;
         initdone = true;
-        int commandDownMask = GuiHelper.getMenuShortcutKeyMaskEx();
+        int commandDownMask = Main.platform.getMenuShortcutKeyMaskEx();
         groups.put(NONE, -1);
         groups.put(MNEMONIC, KeyEvent.ALT_DOWN_MASK);