TL;DR We have decided to not (re-)turn on throttling of timeouts from tracking scripts, and also remove throttling of timeouts from tracking scripts altogether.
This feature was, in the beginning, only intended for tabs in the background, but experiments were also conducted to see the effect of throttling for foreground tabs. These experiments showed that users became inclined to abandon pages to a higher degree than before, and after letting the feature be turned on for Nightly for a period of time, issues that would actually block user interaction were noticed. Actually being able to resolve these issues for foreground tabs is difficult, especially in light of how we schedule timeout events after the rewrite that allowed us to only use a single timer per window[1,2]. Even being able to solve the issues related to throttling of background tracking timeouts would introduce unwarranted complexity, and by instead removing throttling of timeouts from tracking scripts we would reduce complexity of timeout handling. The silver lining is that the importance of throttling of timeouts from tracking scripts has been reduced since we started throttling all timeouts from background windows using the background execution budget, to the degree that we are confident that throttling of tracking timeouts is not as necessary anymore. Cheers, Andreas  Bug 1363829: https://bugzilla.mozilla.org/show_bug.cgi?id=1363829  Bug 1371787: https://bugzilla.mozilla.org/show_bug.cgi?id=1371787 _______________________________________________ dev-platform mailing list email@example.com https://lists.mozilla.org/listinfo/dev-platform