Create window that shrinks the desktop

[photonbuddy]

Hi All,

 

Sorry that the title is a bit cryptic ...

 

What I want to do is create a window, kind of like a sidebar, that will cause other windows, when maximised, to maximise and not cover the created window, whilst also not being covered by the created window, which has been created using the $WS_EX_TOPMOST flag.

 

Is such a thing possible?

 

Any help is much appreciated.