how to change the background color of the image window in labwindows?

[powerpc]

I use "imaqDisplayImage" function to display images from frame grabber continuously. When the size of the image is smaller than the given window which I want to make it maximal, the remaining part of the window is filled by white grid. But I do not want this. I want to change it into black.
I did not find any functions in Labwindows about it,I even tried to get the handle of the window and used SDK to change it. But it did not work.
How should I do? By the way, I do not want to put the image inside a pannel because I will get slower than use imaqDisplayImage when the zoom is used.
Thank you very much.

[KvZ]

This is fixed functionality in the IMAQ Window Display and can not be changed using the IMAQ functions. If you display a image you can use the set size function to size the window to the same size of the image.

Met vriendelijke groet / Kind regards,

Karsten
Applications Engineer
National Instruments