Gah! Selection Brush isn't working!

[DeathByNightElf]

I have it selected but it isnt working, why isn't it?

 

[DisTurBeD-OrC]

My button really doesn't work properly either so I use a hot key. If you press the spacebar you goto the selection brush. Or go under tools and click selection brush. If that doesn't work maby reinstalling warcraft III...