diff --git a/Apps/Explorer/desk_server.vp b/Apps/Explorer/desk_server.vp
index 3b190ae..102a870 100644
--- a/Apps/Explorer/desk_server.vp
+++ b/Apps/Explorer/desk_server.vp
@@ -1150,6 +1150,12 @@ class DeskServer:
         self.next_z += 1
         s.z_order = self.next_z
         self.focused = win
+        # 层级变化会改变窗口互相覆盖的关系：把所有可见窗口整体置脏重画，
+        # 否则被抬起的窗口只重画标题栏，内容区仍露出原来压在上面的窗口，直到鼠标经过。
+        for i in range(desk.DESK_MAX_WIN):
+            w: desk.WinSlot* = self.slot(i)
+            if w.used != 0 and w.active != 0 and w.minimized == 0:
+                self.mark_win(w.uy, w.h)
         self.mark_titles()
 
     def _move_cursor(self, dx: int, dy: int) -> int: