Regression: Tworld and DosBox don't work

Tested in 43787

Tworld and DosBox are using cmd windows to work. Now seems they arent working at all.

Tworld:
*Decompress it.
*Launch it.
*You will arrive to the first Window.
*Press F1:nothing happens(it should show the Help info)
Also you will notice that it is freezing ReactOS, but no exception is raised.

DosBox:
*Install
*Run It.
*It will launch two Command Windows.(Dont move the mouse while it is loading)
*The second one has a Blinking caret, waiting your Input.
*Move the Mouse over the window.The caret will stall and all ReactOS too.

Same thing it stalls but not exception is raised.

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The guilty commit is: 43119
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[win32k]

• Giannis Adamopoulos: Don't do callbacks to usermode when holding the lock. Fixes the famous "VMWare video driver installer 2nd stage hang" bug. Signed off by James Tabor.
  See issue #2666 for more details.
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