TOC Title Folder is Missing

Oops. I misread the question. Thanks Amber for giving a better answer.

Assuming RH2019 New UI or newer, if you think you dragged it somewhere else in your TOC and can't find it, you can do a search (Ctrl +F) in the TOC for the folder name, then double-click on the folder to open that location in the TOC. Then you could drag and drop it back to the correct place. If the folder appears in multiple places in the TOC, you'll see the folder listed multiple times, so you'll have to double-click on each one to find the one that's in the wrong location.

Also, if you notice straight away that you made a mistake, you can undo the change by clicking the Undo button, or press Ctrl+Z. That will only work if you realise the error immediately, though.

You can drag a folder from the Contents panel to the TOC. The topics in the TOC will be in the same order as in the Contents panel but you can rearrange them in the TOC.

The other option would be to go to Explorer and copy the .toc file from a backup. Both projects should be closed. Make sure you have a backup of the current version as well before you start.

Safer to fix it in the current version if you are not sure.