I just realized something.
In version 11, when I would go to save my session or workspace if I clicked on a file in the save dialogue box, the filename that I clicked on would auto-populate (this made it easy to write over files).
Now, in version 12, when I click on a file in the save dialogue box, nothing happens (except the word "untitled" is un-highlighted.
Thinking back over it, this has happened since the Beta. It is nothing more than a nuisance, but i figured if no one ever mentions it, it cannot be fixed.