A duplicate of:
http://tweaker.userecho.com/topic/515777-taskbar-b...

Fixed in v4.5.4.

Please try 7+ Taskbar Tweaker v4.5.4.

I managed to reproduce the issue. I believe that it should be fixed in v4.5.3.1 beta. Please try it.

I cannot reproduce it. Screenshot below.
Please provide the following:

• Your OS version.
• A screenshot of your tweaker options.
• A screenshot of your taskbar properties.
• A screenshot where the bug can be seen.

Mostly fixed in v4.5.2.
The unfixed parts were filled as a separate report:
http://tweaker.userecho.com/topic/515930

Fixed in v4.5.2.

Fixed in v4.5.2.

Should be fixed in v4.5.3.
The issue existed since v4.5.1.8 beta (September 21, 2014), but unfortunately nobody has reported the bug until the final version was released.