Slow Everything Placement?

Hey everyone, Im working on that Erm... Pokemon map I made some threads about a while back, and I got about half way through, and unit/doodad/cliff placement became Incredibly slow, it takes like 5 seconds to place a single tree.

Anybody know whats wrong? I dont have the slightest clue as to what I did wrong.

1) Try closing the brush list windows

2) Is something (An unit or a doodad ) above A start location?

i have the same problem, worldcraft turns really slow when i place units, not doodads. when i hit ctrl+alt+delete it stay normal again 0_o weird hein?

Edit: OMG!!!!I took units off start locations and everything is normal again!! THANK YOU SO MUCH! I cant thank you enough, my map will finish SO much faster now, thank you!