Webextension performance issues on Firefox 56 (Windows only)

Hi,
I’m currently developing a new version of the iGraal extension for chrome and Firefox using the Webextensions API.

My problem is that after the latest Firefox update (Firefox 56) my extension is extremely slow on windows. I don’t have that issue on macOS with Firefox 56. Opening the extension’s popup is very slow as is injecting scripts in web pages.

With Firefox 55 and prior versions my extension works fine on Windows and macOS. I tried the beta of Firefox 57 and again my extension works wonders on macOS and Windows.

The iGraal extension is quiet complexe. It uses the sendMessage API to communicate between the background, extension popup and other injected scripts. It also uses the tabs API a lot.

So I tried multiple things to find out why the extension is slow only on Windows with Firefox 56… I did mock the data sent by the background to the popup to eliminate the sendMessage factor, and my popup opened quickly. But I still had slowness issues with my scripts. I tried to remove the few calls to the local storage but it didn’t change anything.

So this is why I’m contacting you, I’m running out of ideas… I really don’t understand why I have this problem only on Windows with Firefox 56… I tried to gather some information on the version changelog, but I found nothing relevant.

Resolved after 56.0.1 update