brundlefly
This is an old bug with some loops in Dim Pro. It's the drum loop itself, not the timeline looping that's the problem. Here's an old thread about it:
http://forum.cakewalk.com/FindPost/2459815
Thank you brundlefly - i tried that loop (dl_100_k03_lp02) and surprise : no problem at all at 80 and 100bpm !
Hope that one day this problem will be fixed !