Support for the Windows 10 April 2018 Update was added in 7+ Taskbar Tweaker v5.5.

Please provide more details - which version of 7+ Taskbar Tweaker are you using? Do other options work? Do you see any error message?

Support for the new version is being worked on. Please see this topic for more details:

https://tweaker.userecho.com/communities/1/topics/760-support-for-windows-10-spring-creators-update

На данный момент последняя версия программы 7+ Taskbar Tweaker не поддерживает версию 1803.
Подробности:
https://tweaker.userecho.com/communities/1/topics/760-support-for-windows-10-spring-creators-update

Can you make a screenshot of how it looks with and without the tweaker?

Also, can you try the arranging options with all of the tweaks off (but with the tweaker runnign)?

If the arranging options work correctly with the tweaks turned off, please try to isolate the problematic tweak by enabling them one at a time.

Actually, it helped me focus less on testing and more on fixing. So all three issues should be fixed in the newly released alpha version :)

See the following blog post for the update progress:

http://rammichael.com/7-taskbar-tweaker-for-windows-10-spring-creators-update-early-alpha-version

That was already reported here:

https://tweaker.userecho.com/communities/1/topics/731-second-monitor-display-seconds

Please try the beta version, which has a fix for the issue.

Actually, 7+ Taskbar Tweaker v4.1 indeed sets the volume control program to run in higher priority, so that it will launch faster. There's no reason to set the tweaker itself to run in high priority, since most functionality actually runs from within explorer.

Closing. If the topic author had something else in mind: feel free to leave a comment.