diff --git a/libs/gtkmm2ext/keyboard.cc b/libs/gtkmm2ext/keyboard.cc
index 0f9aeb028f..d59fe014ce 100644
--- a/libs/gtkmm2ext/keyboard.cc
+++ b/libs/gtkmm2ext/keyboard.cc
@@ -143,18 +143,6 @@ Keyboard::Keyboard ()
 
 	RelevantModifierKeyMask = (GdkModifierType) gtk_accelerator_get_default_mod_mask ();
 
-#ifdef __APPLE__
-        /* Remove SUPER,HYPER,META.
-         *
-         * GTK on OS X adds META when Command is pressed for various indefensible reasons, since
-         * it also uses MOD2 to indicate Command.
-         */
-
-	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~GDK_SUPER_MASK);
-	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~GDK_HYPER_MASK);
-	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~GDK_META_MASK);
-#endif
-
 	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask | PrimaryModifier);
 	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask | SecondaryModifier);
 	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask | TertiaryModifier);
@@ -164,6 +152,29 @@ Keyboard::Keyboard ()
 
 	gtk_accelerator_set_default_mod_mask (RelevantModifierKeyMask);
 
+#ifdef __APPLE__
+        /* Remove SUPER,HYPER,META.
+         *
+         * GTK on OS X adds META when Command is pressed for various indefensible reasons, since
+         * it also uses MOD2 to indicate Command. Our code assumes that each
+         * modifier (Primary, Secondary etc.) is represented by a single bit in
+         * the modifier mask, but GTK's (STUPID) design uses two (MOD2 + META)
+         * to represent the Command key. Some discussion about this is here:
+         * https://bugzilla.gnome.org/show_bug.cgi?id=692597 
+         *
+         * We cannot do this until AFTER we told GTK what the default modifier
+         * was, because otherwise it will fail to recognize MOD2-META-<key> as
+         * an accelerator.
+         *
+         * Note that in the tabbed branch, we no longer use GTK accelerators
+         * for functional purposes, so this is as critical for that branch.
+         */
+
+	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~GDK_SUPER_MASK);
+	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~GDK_HYPER_MASK);
+	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~GDK_META_MASK);
+#endif
+
 	snooper_id = gtk_key_snooper_install (_snooper, (gpointer) this);
 }