For years I have had "four finger click" setup to do a "Command + W" on my Apple trackpad.
I find it so easy to close tabs and windows this way. Recently (maybe a few months ago) it has stopped working all the time with Firefox. Sometimes it works without issue but other times I have to take my fingers off the trackpad or "click" within the window (even though it is already selected) and then I am able to do the four finger click and then it will work.
This occurs with my Apple Wireless Trackpad as well as the trackpad built in to the laptop.
Type of Mac: Late 2013 MacBook Pro 13"
macOS version: 10.12.6
BetterTouchTool version: 2.500