Virtual StringTree's hint windows are left out on the screen

See this screenshot, in the middle it's the small hint windows that are generated by a TVirtualStringTree control and were left out on the screen, these hint windows will remain there until the application exits. the problem happens when the treeview's hint is shown and the mouse leaves quickly to the window next to it.

Any idea about how to avoid this or how to clear those un-erased hint windows if it's difficult to avid this?

Few days ago I asked a similar question, while the hint windows in the screensh开发者_StackOverflow社区ots look the same, the are not the same problem. That problem, the hint text never shows and only that kind of uncompleted hint windows are shown; This problem, the hint text shows but the hint windows are not completely erased in a case (as I described above). Hope it's clear.

Does it help to just repaint the window?

If this is a Word addin that may be a reason.

Maybe you should create your own hint window class (inherit from TVirtualTreeHintWindow) which instance you can manage by yourself and then override the GetHintWindowClass method to use this class.