Hi, do you mean that you can't combine the objects?
If so, try to delete history (Edit > Delete by Type > History), or you can click on the option of combine, and try out different settings.
:)...

I had the same issue before, here's the solution I figured out.

1. Go to UV > UV set Editor.
2. Rename "all the object's you want to combine" to the "same" name. (select the object one by one...