1888773 - There's a chance that _tabDropIndicator won't be hidden

Status: RESOLVED WORKSFORME

(Core :: Widget: Gtk, defect)

Description

[jackyzy823]

I'm not sure how to reproduce, but there's a chance that _tabDropIndicator won't be hidden automatically. You need manually drag tabs around to hide it.

There's also a description and screenshot from a Reddit thread: https://www.reddit.com/r/firefox/comments/1ab87im/firefox_changing_tabs_itself/kjtivpk/?context=3

Also, the reddit user and i are using same desktop environment : KDE Plasma. I'm not sure if it is related.

I add some debug breakpoint/ log in chrome://browser/content/tabbrowser-tabs.js and found out that

Uncaught TypeError: dt is null
    getDropEffectForTabDrag chrome://browser/content/tabbrowser-tabs.js:1980
    on_dragover chrome://browser/content/tabbrowser-tabs.js:566
    handleEvent chrome://browser/content/tabbrowser-tabs.js:1848
    getDropEffectForTabDrag chrome://browser/content/tabbrowser-tabs.js:1980

Comment 1

[jackyzy823]

According to the example from https://developer.mozilla.org/en-US/docs/Web/API/DragEvent/dataTransfer , dataTransfer might be null

Comment 2

[jackyzy823]

Attachment: Bug 1888773 - Prevent error when dataTransfer is null in getDropEffectForTabDrag. r=#tabbrowser-reviewers

Comment 3

[Gregory Pappas [:gregp]]

Wasn't this fixed in bug 1875031?

Comment 4

[jackyzy823]

Oh, sorry , i haven't notice that :(

But i think this patch is still worthwhile.

Comment 5

[Mike Conley (:mconley) (:⚙️) (PTO June 8 - 12)]

Hey jackyzy823,

So the module owners and peers talked about this a bit, and we thought maybe what'd be better here is to try to write a test that exercises some native dragging and dropping and ensuring that the dataTransfer property exists (because it should always exist). Are you interested in doing that?

Comment 6

[jackyzy823]

Hi mconley .

Are you interested in doing that?

I'm ok with helping , but i have little knowledge about this.

Comment 7

[jackyzy823]

I found that my approach doesn't work :( Also Fixes in bug 1875031 didn't work either, it still reproducible with Nightly (20240404)

Comment 8

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

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

For more information, please visit BugBot documentation.

Comment 9

[Dão Gottwald [:dao]]

jackyzy823, I'm removing you as the assignee here for now, as we don't have a clear path forward.

emilio, since you worked on bug 1875031, any idea why the dataTransfer might still be null?

Comment 10

[Emilio Cobos Álvarez [:emilio]]

I think this is https://bugs.kde.org/show_bug.cgi?id=464196 which was a KDE+GTK bug, and is fixed upstream.

Comment 11

[Emilio Cobos Álvarez [:emilio]]

Jacky, can you confirm that if you use an updated KDE plasma version this doesn't reproduce anymore?

Comment 12

[jackyzy823]

Hi, i updated to KDE 6 (with Fedora 40) , it seems work normally now.