Perhaps you're using an insider build of Windows 10?

See the discussion and my reply here:

https://rammichael.com/7-taskbar-tweaker/comment-page-39#comment-10041

What do you mean? Please provide more details.

The standard menu is a Windows feature, and can be activated by holding the Shift key (7+ Taskbar Tweaker merely allows to use it without Shift). Applications are allowed to customize this menu - for example, Chrome adds items such as "New tab" and "Task manager". Unfortunately, some apps carelessly disable the menu altogether, probably not deliberately, but since the standard menu is not the default since Windows 7 it's not being noticed.

It's not in my bucket list. In fact, you're the first user to report this issue, and I can't reproduce it on my computer.

Update KB4482887 introduced an incompatibility with 7+ Taskbar Tweaker v5.6. Updating to v5.6.1 should solve the issue.

Will be available in next version (that means that you'll get the old behavior one last time in the next update, since the current version will handle the vbs).

Fixed in v5.6.1.

I've released a new beta version, v5.6.0.4, which should fix the incompatibility. Please try it and let me know if there are any other issues.

i have usually no empty space on my taskbar to click

There's the "Reserve empty space on taskbar" option just for that.

You can also configure a keyboard hotkey for this, or configure a custom mouse hotkey for the "show desktop" button (e.g. Shift+click or middle click).

That's not exactly what you've asked for, just mentioning other options.