[Affected versions]:
Nightly 79.0a1 (2020-06-23)

[Affected platforms]:
Platforms Mac 10.14

[Preconditions]
Have devtools.responsive.browserUI.enabled = true

Steps :

1- Launch the Firefox browser and reach about:compat
2- Hit Ctrl+Shift+M in order to start Responsive Design Mode with touch simulation off (make sure to check reload when touch simulation is toggled option)
3- click any enable button
4- Nothing happens
5- activate touch simulation
6- click any enable button
7- options change accordingly
8- disable touch simulation
9- click enable/disable buttons
10- buttons still work.

Expected Results :
The user should be able to enable/disable compat options with RDM enabled or disabled.

Actual Results :
The user needs to activate touch simulation first in order to enable/disable compat options.

Hi, in beta 79.0b5 (64-bit) disable/enable are only working with touch simulation off, contrary to the bug's description

Best regards,
Clara