Problem with some shaders in fullscreen

hello world, the other day i was messing up with some new patches that im doing and I found a problem in some shaders when i go on fullscreen in windows xp, for example with the multiscreen node, when i go on fullscreen , the softedge shader, dont works, it dissapear, but in windowed mode not, it has to do with the graphic card config,??
The same happens with the alphablend shader, the blend modes dissapear on fullscreen , Anyone know about this, ?
It is A bug, or its configuration, it a little frustration for me , thank in advance for the reply.