1326002 - Clicking tab close button can have a lot of lag.

Status: RESOLVED DUPLICATE of bug 1328283

(Firefox :: Tabbed Browser, defect)

Description

[Jeff Muizelaar [:jrmuizel]]

It seems like closing a tab requires communicating with the child process. This can result in very noticeable delays between the initial click and the tab actually going away. This seems unnecessary.

Comment 1

[Mike Conley (:mconley) (:⚙️)]

I believe this is due to the fact that we need to ask the content of the tab whether or not an unbeforeunload handler has been set to return something which will necessitate showing the unload dialog.

Comment 2

[:Gijs (he/him)]

comment #1 is correct. See bug 1325527 for some idea to provide user feedback, and bug 1328283 covers potentially pushing up info on whether there are any beforeunload handlers to the parent so it doesn't need to check with the child before closing. I'll dupe this there as there isn't a lot else we can do. Note that as Bill pointed out in bug 1328283, even if we do push things up in theory we might occasionally violate the spec and close tabs because the handler is attached right before a user closes the tab, and the message from the child has not gone up to the parent yet. I think that's probably fine, but it's something to keep in mind.