Not sure what more to say but my isometric tiles aren’t appearing in the Tile Collision Editor.
My tiles are large, they’re 256x128 pixels.
Here’s a screenshot of what I’m seeing:
Are you still having this problem? I haven’t seen it before and don’t know what could be going on either. If this is with Tiled 1.0.3, did you try using the latest development snapshot to see if it fixes the problem?