Here is a little tip I picked up about refresh and hosting AROS in Linux. If you are in AROS and you are having trouble with the windows getting blacked out, AROS is not at fault. For example, if I drag a window off the screen a bit and bring it back into full view, half the window is blacked out.
To fix this, edit your config file for X Windows. XF86Config if you are using XFree86 and xorg.conf if you are using Xorg. These are usually found in your /etc/X11/ directory. Edit the file and find the "Device Section". Then input a line that reads "Option "Backingstore"". Without the outside quotes. Save the file and logout and back into your desktop environment. This should take care of the blacked out window problem in AROS.