This article was previously published under Q92526
Microsoft Windows version does not support fully functional transparentwindows.
If a window is created using CreateWindowEx() with the WS_EX_TRANSPARENTstyle, windows below it at the position where the original window wasinitially placed are not obscured and show through. Moving theWS_EX_TRANSPARENT window, however, results in the old window backgroundmoving to the new position, because Windows does not support fullyfunctional transparent windows.
WS_EX_TRANSPARENT was designed to be used in very modal situations and thelifetime of a window with this style must be very short. A good use of thisstyle is for drawing tracking points on the top of another window. Forexample, a dialog editor would use it to draw tracking points around thecontrol that is being selected or moved.
In Windows 2000, specific colors in a window can be made truly transparentby giving the window the WS_EX_LAYERED extended style and callingSetLayeredWindowAttributes.