Steps to reproduce:

1. On a wiki (e.g. mediawiki.org) click on Preferences → Set your global preferences.
2. Click on "Select options below to be global", the text, not the checkbox.

Actual result:
The checkbox gets checked, but the options below are still disabled.

Expected result:
The checkbox gets checked and the options below are enabled. Alternatively, nothing happens when the label is clicked.

Additional information:
This only happens under the "User profile" tab. For the rest, the text isn't clickable.

I've managed to reproduce this in both Firefox (65.0.1) and Chrome (72.0.3626.121).