It's about crossing the threshold into another space (room).
I learned it from watching Q.I.
cheers, Mark
Yep, and the weird thing is that if you walk back to the room where you first thought of something you have a good chance of remembering again.
Mantra: No more pedals, must finish BlueyCaster...
Disclaimer: I haven't done woodwork since high school, and wasn't really paying attention at the time ...