Make menu rows have equal heights

[Hajas Barnabás <hajbazer gmail com>]

Dear GTK Community,

I need your help. I would like to make GTK menu item rows to have equal heights.

When a menu item has an icon, it will have a height of 21 pixels.

When a menu item doesn't have an icon, it will have a height of 19 pixels.

This is visible and is somehow annoying because it gives me the
feeling of an inconsistent UI.

See: https://i.imgur.com/sEO67k6.png

My theme is Xfce-basic and I'm using Xfce 4.10.1-10 on Debian Jessie.
This is only present at GTK 2 apps and I'm looking for a solution for
GTK 2.

What should I write to ~/.gtkrc-2.0 in order to have the 21 pixel
height, even at rows with no icon?

Thanks
Barnabas Hajas