Ok, I fixed it at version 1.3a1
Pleaze check "About this Add-on" or wait version 1.3 is signed.
thanks.

Update:
﹥if there is only one tab open, "closing tab" gesture doesn't work in that case...

Thank you for bug report.
I try.
I'm sorry if can't fix it.

﹥Also a little request, new tab gesture opens "about:blank" but it would be better if it opens "about:home" ...

i think so too, but "Webextensions" can't open "about:home" or "about:newtab".
thx.

Update2:
hmm.... i didn't change the closing process.
It may be there are some conditions.

Update3:
I finally fixed "closing tab" at version 1.7 !