Sub-folders of Tabs, Dump Tabs when moved in a Folder List

[SheepDomination]

Preliminary Checks

• I have read and understood the important section above.
• I have searched existing issues and avoided creating duplicates.
• I am not filing an enhancement request.
• I have checked that this issue cannot be reproduced on Mozilla Firefox.
• I have checked that this issue can be reproduced once I removed all my Mods and Custom CSS.

What happened?

I create a sub-folder within a folder, this sub-folder is the last item in the folder, in other words; even if there are tabs, it's the last item just a folder in the folder list.

Expected behavior

Move the folder along with the tabs in the sub-folder to the top of the list above all other tabs keeping the tabs in the sub-folder

Actual behavior

When moving the sub-folder to the top of the list, all the tabs in the sub-folder were dumped out of the sub-folder and back into the folder tab list

Steps to reproduce

Create a folder, make sure in this folder there are numerous tabs. Then create a sub-folder which should be the last item in the list of items including tabs. Place tabs into this sub-folder. Check to see that those tabs are within the sub-folder while it remains the last item in the list within the folder.

Move the newly created sub-folder to the top of the list just below the folder, try to open the sub-folder within the folder, all the tabs will be dumped out back into the main folder list.

Screenshots and videos

Version

1.15.3b

What platform are you seeing the problem on?

Windows - x64

What component is this issue related to?

Tab Folders

Relevant log output if applicable

[Propheticus]

I've tried this several time in different combinations and permutations, unloaded or not and yet I have not been able to get tabs to be 'dumped' out of their subfolder once.
So for now I am unable to reproduce.
Could a combination with mods or (CSS) tweaks be at play?