976621 - Dragging a tab from one Browser window to an [e10s] Browser window breaks

Status: VERIFIED FIXED

(Firefox :: Tabbed Browser, defect)

Description

[Rob Campbell [:rc] (:robcee)]

1. Open a "New e10s Window" (on mac, I guess)
2. Drag a tab from the original window to the new e10s window

expect:
tab moves from one to the other, document loads, etc.

actual:
new tab gets created with the right favicon but no document gets loaded in the e10s window. Original browser window keeps the tab in tab list, but it isn't selectable, has no document.

Comment 1

[Rob Campbell [:rc] (:robcee)]

also have this on the Browser Console:

tabview assert: should already be linked
TabItems_update@chrome://browser/content/tabview.js:5661:7
TabItems_onMozAfterPaint@chrome://browser/content/tabview.js:5651:7

Comment 2

[Boris Zbarsky [:bzbarsky]]

Presumably some exception getting thrown partway through the swap code?

Comment 3

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

I'm not sure what we really want to do here. We could keep the tab running in the chrome process, but that's probably not what the user wants. The only way to move it into the content process is to use session restore, but that causes potential data loss.

Also, the "New e10s window" thing is only for nightly. We're never going to ship it, so we shouldn't invest too much in it. But this is the second time someone has mentioned this bug. Maybe it's worth doing something.

Comment 4

[Tim Taubert [:ttaubert] (inactive)]

I agree that it doesn't make a lot of sense to implement dragging tabs between e10s and non-e10s windows. I think the easiest thing to do is to just prevent dropping a tab there in the first place?

Comment 5

[:Felipe Gomes (needinfo for replies!)]

Yeah, for similar reasons, we don't allow moving tabs from a regular window to a private browsing window too. The drag&drop indicators simply don't show up as a target in the other window, so the user understands that no drop will occur. We should probably just do the same for the e10s window.

Of curse, we must take a look at what happens when dragging from one e10s window to another.. (on a separate bug). It could get complicated depending on how we partition the processes in the future. So this interaction is worth keeping in mind when thinking about that.

Comment 6

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

Attachment: tab-drag

OK, I guess that's pretty easy.

Comment 7

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/c5a7f033a90c

Comment 9

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/c5a7f033a90c

Comment 10

[Tracy Walker [:tracy]]

d&d tab to e10s from standar browser window just opens new standard browser window.