Maybe this is not the right forum, but it is a question related to graphics programming, so...

A friend of mine has Windows 7 on his laptop, and DirectX runtime is not installed (except for the Direct2D libraries (I think – no more DirectDraw, right?) that apparently come with Windows). Now, we were playing some Sega Genesis games using the Gens emulator, set to use “DirectDraw” option since Direct3D is not available.
If u ever used this emulator, you know that when u run it the screen turns black for a moment, while the program initializes its graphics system.

I noticed that Windows 7 changes its behavior while Gens is running, in terms of UI presentation – the blurry window frame becomes solid, app thumbnail representations (when you hover the mouse pointer over an app button on the taskbar) are replaced with text, etc.

Is this a result of Windows readjusting itself to the available resources, or the program somehow changes the way Windows draws its UI? Is the latter even possible?