Inspector UI changed - can't edit tags!

Unity Engine
1

Hi, folks. Odd problem here. My UI changed for whatever reason, and I no longer have a drop-down list for layers or tags. I can still manually enter the layer number, making the inability to edit tags the more pressing issue. I started a new project and the problem didn’t carry over, confirming that this issue is associated with my project files. How do I restore the original UI?

Reference image: http://i888.photobucket.com/albums/ac82/Premonition2035/Unity%20Development/Tags2.png

You can ignore the scene view; I may as well just have snapped the Inspector.

2

Any thoughts? I’ve already explored the Inspector settings trying to find a way to reverse this. I don’t know what I could have done, or if it’s my fault to begin with. I’ve never extended the editor to modify the Inspector, and there’s no information on this problem that I can find.