.Map :: MoHAA Mapping

hey all. I was using the free roation 'r' thing to flip around a triangle I was using to frame a roof... then suddenly it became ultra slim(like a mesh) and was unable to be selected. I had saved it right then without noticing as well, so it will cost me a couple hours at least if I cant fix it =)

Does anyone know what exactly I may have done?
and/or
How I could select or delete this evil triangle?

Whatever happened, it is likely the fault of this crap mouse. The buttons on these microsoft infrareds get worn down and dont hold, you end up clicking everything 5 times because it releases as you hold it. What lousy products, its not like its old, I have several really old mice with perfect buttons... but I digress..

Thanks in advance if anyone knows what is going on here.

if it is the last brush you made use find brush in I believe it is the edit menu and find brush 0