Hello,
Almost all of the features are completely free, including cloud synchronization.
Only upload and download of thumbnails is paid feature (my clod server is currently not capable to handle this feature for all users).
Also I would like to point out that I'm developing this addon for more than 18 months with minimum income from the Pro versions sales.

Have a nice day :)

Best regards,
Juraj Mäsiar

Hello,

I'm really sorry for the inconveniences, but please understand my situation. I'm just using the tools I have available. If the tool is broken, all I can do is complain to the manufacturer.
Currently the tool is the IndexedDB database and the manufacturer is Firefox. And the situation is even more complicated because of other software in your PC that want to "help" you by cleaning and corrupting your Firefox database.

Best regards,
Juraj Mäsiar

Hello,
Your groups are there, you just don't see them. The group-list is actually scrollable, but you can also:
1) increase Group list height to 50 in Options page / Groups tab, to see two rows of groups (you can also decrease font size or reduce spacing)
2) use group-dials instead to navigate between groups, you can see that in the introduction video with the group-dial "Work" (https://www.youtube.com/watch?v=wvT4w-R8hJU)
3) rename groups with long names :)

But as a user with 3 big monitors I can also recommend you to buy a bigger screen, like 27" with QHD resolution (2560x1440) - it's a great way to increase productivity and you can fit a lot of groups there.

I hope this helps.

Have a nice day :)