Fix mouse_warping

sway/input/seat.c

@@ -709,8 +709,15 @@ void seat_set_focus_warp(struct sway_seat *seat, struct sway_node *node,
 		}
 
 		if (config->mouse_warping && warp && new_output != last_output) {
-				double x = container->x + container->width / 2.0;
-				double y = container->y + container->height / 2.0;
+			double x = 0;
+			double y = 0;
+			if (container) {
+				x = container->x + container->width / 2.0;
+				y = container->y + container->height / 2.0;
+			} else {
+				x = new_workspace->x + new_workspace->width / 2.0;
+				y = new_workspace->y + new_workspace->height / 2.0;
+			}
 			if (!wlr_output_layout_contains_point(root->output_layout,
 					new_output->wlr_output, seat->cursor->cursor->x,
 					seat->cursor->cursor->y)) {