Hi there!
I think 2D Toolkit is awesome, but it's not the first time I run across the same issue. The thing is that once I've built my tilemap, I want to set some colliders (specifically the ground) so my player doesn't fall. My player has a Rigidbody2D and a BoxCollider2D and I set the Box Trimmed collider option to my ground tile and I hit commit. When I select in the Hierarchy view the Tilemap Render Data, the collider mesh should appear, but it's seems to be missing.
Following this tutorial (
http://www.unikronsoftware.com/2dtoolkit/doc/2.10/tilemap/tutorial.html) also happened to me once. I had to set each collider one by one and making sure the mesh didn't disappear. I finally did it this way, but I think it's far from what should be done.
What am I doing wrong? My collider depth is set to 10 too, but still nothing happens. I'm using 2D toolkit 2.3.3 with Unity 4.3.3f1.
Thank you!