Regarding a visual separator, there's no such functionality but you can use an empty icon as a workaround, see the discussion here:

https://rammichael.com/7-taskbar-tweaker-v5-2-with-support-for-windows-10-anniversary-update/comment-page-1#comment-7194

Regarding "real groups", I don't know what you mean by "real", but you can create a group with either Taskbar Inspector, or by using the "Drag within/between groups using right mouse button" option. Then you can use "Decombine: On mouse hover" and other related options to "close and expand" the groups.

At least you found it :) thanks for posting an update.

I don't quite understand what you mean.

Could you post an image or a video that demonstrates the problem?

It's a false positive, and according to VirusTotal the detection is now removed:

https://www.virustotal.com/gui/file/0f1a062fcff547c3068caeb2c87a19b5c3165b33b58805c7cc707327cc987c45/detection

Thanks for submitting it to F-Secure.

What do you mean by "failing"? Do you see an error message? Can you share a screenshot?
Perhaps your antivirus blocks the download. You might want to try turning it off and turn it back on after downloading and installing the tweaker.

Please make sure that you're indeed using 7+ Taskbar Tweaker 5.9.1, and not an older version.

This should be fixed in v5.9.1.

Why? It will be a boring window if I do.

Here are three test versions:

https://www.dropbox.com/sh/2esrbdiyanta12m/AAD3jSnlZNZdaL_EteuRuzkfa?dl=0

Each additional test version (in increasing order of the numbers) removes more functionality. Please make sure that all options are disabled, then try using test1 for a while. If you still have the issue, try test2, then test3, until the issue is gone. Let me know which test, if any, causes the issue to be fixed.

Perhaps you had the previous version cached in the browser. Please try downloading it again. If it doesn't work, try downloading it in incognito mode.