I’m trying to use the collision editor but the zoom text is highlighting so nothing works 
I don’t know what you mean with “the zoom text is highlighting”. Can you be more specific or provide a screenshot?
In general, if the tile collision editor isn’t working, it’s usually because you’re using an external tileset. You can’t edit a tileset while it is external, so you’ll need to temporarily import it. This will be fixed in Tiled 1.0 (I’m mostly done fixing it on the wip/tilesetdocument branch, but it caused a huge amount of changes).
Oh thank you, I fixed it 
and by highlighted I mean like this
(I thought that was the reason)
Ok, great that this was your problem. 
I’ve merged the wip/tilesetdocument branch into master and the changes are now available in the snapshot builds. So if you’d like to give those a try, then you can avoid the “temporarily import the tileset” workaround. Since this represents quite a big change to Tiled, feedback is welcome.