Incorrect Start menu width on Zorin OS 15

[Mhowser]

Here is the start menu with default Gnome theme.

And here is the Arc-dark theme applied.

Details

• Distribution (with version): Zorin OS 15
  • Base distribution (if have, with version): Ubuntu 18.04
• Desktop environment (with version): Gnome 3
• Arc version/commit (don't put "latest"): 20190330
• GTK+ 3 version: 3.22.30-1ubuntu3
  • Murrine engine version: 0.98.2-2ubuntu1
  • gnome-themes-extras version: 3.30.2
• Installation method (package or source): Apt package

[fossfreedom]

Would like some help here since not a zorin user. pull requests welcome thx

[Mhowser]

I still want to fix this, but not sure how to start.