Cleanest way here is not do bounding box collision for editmeshes at all. Decision is taken because: * Usually we want to do the snapping to the edited mesh anyway (when we don't the mesh is skipped completely, so we don't need to worry for extra checks) * Bounding box is calculated from derived mesh. This means that for subsurfed meshes for instance, the bounding box may be significantly smaller than the size of the edit mesh.