[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:preferences
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 icon listed (general, home, search,etc)
4- activate touch simulation
5- click on icons mentioned in step 3, (icon, not text)
6- icons are highlighted as if having performed double click
7- click privacy and security
8- click on the enhanced tracking protection options (standard, strict, custom)
9- clicking text selects properly, clicking icons highlights each of them.

Expected Results :
performing single click should not highlight when having touch simulation on.

Actual Results :
Touching icons listed in about:preferences will get highlighted with touch simulation ON.

Hi, in beta 79.0b5 (64-bit) a double click is required for settings to be taken into account (for example checking enhanced tracking protection options). See bug https://bugzilla.mozilla.org/show_bug.cgi?id=1648112

Best regards,
Clara