--- a/x11-clipboard-manager/gsd-clipboard-manager.c	2020-01-22 07:32:02.000000000 +0800
+++ b/x11-clipboard-manager/gsd-clipboard-manager.c	2020-01-26 18:49:33.013864719 +0800
@@ -222,8 +222,10 @@
         GdkDeviceManager *device_manager = gdk_display_get_device_manager (display);
         GdkDevice *device = gdk_device_manager_get_client_pointer (device_manager);
 #endif
+        GdkScreen* screen = gdk_screen_get_default ();
+        GdkWindow * root_win = gdk_screen_get_root_window (screen);
 
-        gdk_window_get_device_position (NULL, device, NULL, NULL, &state);
+        gdk_window_get_device_position (root_win, device, NULL, NULL, &state);
         if (state & (GDK_BUTTON1_MASK|GDK_SHIFT_MASK)) {
                 return TRUE;
         }