diff --git a/src/xpra/client/gtk_base/gtk_client_window_base.py b/src/xpra/client/gtk_base/gtk_client_window_base.py
index 9ad29b534a..56ef921efa 100644
--- a/src/xpra/client/gtk_base/gtk_client_window_base.py
+++ b/src/xpra/client/gtk_base/gtk_client_window_base.py
@@ -936,11 +936,11 @@ def set_modal(self, modal):
         #all other windows we manage from receiving input
         #including other unrelated applications
         #what we want is "window-modal"
-        log("set_modal(%s) modal_windows=%s", modal, self._client.modal_windows)
-        if not self._client.modal_windows:
-            statelog("set_modal(%s) swallowed", modal)
-            return
-        gtk.Window.set_modal(self, modal)
+        #so we can turn this off using the "modal_windows" feature,
+        #from the command line and the system tray:
+        mw = self._client.modal_windows
+        log("set_modal(%s) modal_windows=%s", modal, mw)
+        gtk.Window.set_modal(self, modal and mw)
 
 
     def set_fullscreen_monitors(self, fsm):
diff --git a/src/xpra/client/mixins/window_manager.py b/src/xpra/client/mixins/window_manager.py
index 2ec0431496..447270799b 100644
--- a/src/xpra/client/mixins/window_manager.py
+++ b/src/xpra/client/mixins/window_manager.py
@@ -216,6 +216,13 @@ def cleanup(self):
         log("WindowClient.cleanup() done")
 
 
+    def set_modal_windows(self, modal_windows):
+        self.modal_windows = modal_windows
+        #re-set flag on all the windows:
+        for w in self._id_to_window.values():
+            modal = w._metadata.boolget("modal", False)
+            w.set_modal(modal)
+
     def set_windows_cursor(self, client_windows, new_cursor):
         raise NotImplementedError()