Imported skel mesh wont allow click on skeleton tab or animation tab

I wanted to add a bone to an existing skelmesh but it crashes when reimporting.
If I import the mesh and target it to the skeleton it comes in but I cant select the anim tab or the skeleton tab
But if i import this mesh as new skeleton it imports fine and looks identical to the original in everyway, exsiting animations import to this one just fine. I d like to avoid reimporting all my animations if avoidable, not to mention rebuilding my anim blueprint.

The new bone did get added to the skeleton okay, but since no skel mesh has it its not really in and useable