1648056 - When zooming the add-on manager, select dropdowns in the add-on preferences do not show up in the right position

Status: NEW

(Toolkit :: Add-ons Manager, defect, P3)

Description

[:Gijs (he/him)]

STR:

0. install an add-on that has dropdowns in its preferences, e.g. https://addons.mozilla.org/en-US/firefox/addon/tumblr-post/ or https://addons.mozilla.org/en-US/firefox/addon/min-twitter/
1. open about:addons
2. open the preferences of the add-on installed in step 0
3. zoom in (any zoom pctage will do, the higher the more obvious the effect)
4. open any dropdown

ER:
dropdown opens next to the select box

AR:
dropdown anchor position is too far down / to the right, when zoomed in.

The same thing doesn't happen with menulists in about:preferences , or if I insert a select tag into about:support. So I think it's something to do with about:addons' peculiar setup of having a "remote" (child-process) content browser inside a parent-process tab (which also has its own nested browser...). The zoom level will be set the same on all these browsers, and I suspect we're multiplying it for each viewport, when that isn't what the effect of the zoom ends up being. So this may be a layout bug...

(note: on current nightly/beta, bug 1647727 will mean the dropdown doesn't show up at all. Fix pending on autoland. I did check but this bug manifested before the select parent changes that regressed bug 1647727. Unclear if it ever worked right, I haven't checked.)

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Either this: https://searchfox.org/mozilla-central/rev/46e3b1ce2cc120a188f6940b5c6eab6b24530e4f/layout/xul/nsMenuPopupFrame.cpp#1464-1468
Or this: https://searchfox.org/mozilla-central/rev/46e3b1ce2cc120a188f6940b5c6eab6b24530e4f/layout/xul/nsMenuPopupFrame.cpp#1289-1307

Are the right places to investigate these I think.

Comment 2

[Alice0775 White]

#1 Regression window (dropdown won't open):
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=392ed89ec2730a48d10b1cec741e86a242d28aa3&tochange=a625a2e9b3333a8e76982ea65f077cfded6ac224

Suspect: Bug 1357486

#2 Regression window (dropdown pops up at wrong position when zoomed):
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=b14c76c3291422c490576cd7e49b4a2b2bd95d8c&tochange=42ad059f07ba5057d4dc1b0fe00d96a0ece73bde

Suspect: Bug 1381321

FYI, Set extensions.webextensions.remote to false will fix the issue

Comment 3

[Mark Striemer [:mstriemer]]

I can't reproduce this on Mac, but I do see it on Windows.

That said, zooming doesn't seem to work properly on Mac, either. It seems to zoom just the text, not the page. Same behaviour in Preferences on Mac.

Comment 4

[Mark Striemer [:mstriemer]]

Ah, I somehow had zoom text only set. This reproduces on Mac as well when that isn't set.

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:mixedpuppy, could you have a look please?

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