Two Qt apps getting bleed-through effect

I have two Qt applications that I am running on separate framebuffers on an Embedded Linux OS on PowerPC (though even if they run on the same framebuffer the problem still exists). So one of the applications has its background set as the "clear color" as set up in the device's color map, hence when running the two apps at the same time it shows one essentially being on top of the other (i.e. you see both... one app is an overlaid on-screen menu type app with just some buttons showing). The problem is that when moving the mouse around, I see a kind of "bleed-through" effect... it just paints the areas that I move the mouse over (on the "background" app). It doesn't matter if I turn mouse or mouse tracking off in one app. Both apps are full screen (windowless), but it also doesn't matter if one app isn't full screen... when running it there is a green background that appears and takes up the whole screen behind the app (seems to be how Qt operates in this situation?). Hence, the weird bleeding thing still happens with any two apps. In addition, BOTH apps are receiving all the mouse/keyboard events I send (may be separate issue). If anyone has any familiarity with this type of behavior, would appreciate any insight. I'm not sure if it's a hardware or framebuffer related issue either. Thanks.