Wide menus in web browser

[Smokes]

Hi
I have a favorite theme Castle, absolutely love it. Credit to the person who done this.

I am getting wide menus which only happens in a web browser both with bookmark drop down list & context menu. Regardless of how long or short I list Bmarks. I do prefer to keep names short as I can.
I have tried four browsers, Opera Firefox, Waterfox & Tor. These were all tried installed and portable same result with all of them.

The Red X's are the parts I am referring to. The red box shows where the theme seems to end. Has anyone any idea why this is the only theme it happens with?

Could this be fixed?

Thanks
Smokes