diff --git a/openbox/client.c b/openbox/client.c
index cccc59db..0b03d9d2 100644
--- a/openbox/client.c
+++ b/openbox/client.c
@@ -2874,6 +2874,13 @@ void client_try_configure(ObClient *self, gint *x, gint *y, gint *w, gint *h,
        the updated frame dimensions. */
     frame_adjust_area(self->frame, FALSE, TRUE, TRUE);
 
+    /* cap any X windows at the size of an unsigned short */
+    *w = MIN(*w,
+             G_MAXUSHORT - self->frame->size.left - self->frame->size.right);
+    *h = MIN(*h,
+             G_MAXUSHORT - self->frame->size.top - self->frame->size.bottom);
+
+
     /* gets the frame's position */
     frame_client_gravity(self->frame, x, y);