Skip to main content

Popup Menu is cut off in Firefox

Issue summary

The Popup Menu that is used since MTA 2.0 is not shown correctly when using Firefox.

Popup Menu cut off

MTA will notify users with a red button of this issue after they login. Clicking the button will lead them to the solution described below.

Possible causes and resolutions

This popup menu is using the has selector in CSS. This feature is enabled by default in Chromium browsers, and disabled by default in Firefox. Most other browsers do not support the feature.


To enable the feature in Firefox:

  • navigate to about:config in your Address bar
  • search for has-selector like this: Has selector
  • then, make sure to set the layout.css.has-selector.enabled property to true.
  • restart Firefox and go to MTA to check the menu is working correctly.

More documentation about the has selector on Mozilla: