1930931 - Unloaded tabs cannot be dragged from icon until after they have been loaded

Status: VERIFIED FIXED

(Core :: DOM: Copy & Paste and Drag & Drop, defect)

Description

[Rares Doghi, Desktop QA]

Attachment: Tabs20s.mp4

Found in

• 134.0a1 (2024-11-13)

Affected versions

• 134.0a1 (2024-11-13)
• Beta 133.0b7
• Release 132
• Esr 128

Preconditions
Have a Previous session with a lot of tabs.

Affected platforms

• all

Steps to reproduce

1. Launch Firefox and Restore the previous session.
2. Before the Tabs have a chance to load try to move them around.

Expected result

• The user should be able to move the tabs around even if they have not started to load their content.

Actual result

• Sometimes the user has to click a tab again in order to move them while the first click starts to load the content from that tab.
  Please note that this issue does not happen at a 100% repro rate.

You can see this issue at around second 20 in the attached video

Regression range
Not a Regression.

Comment 2

[Kestrel]

STR:

1. Create a tab and unload it by right-clicking > Unload Tab or from about:processes or close and restore the window.
2. Drag the unloaded tab from the icon. On Windows this must be done before the loading animation finishes.

Expected:
Unloaded tab can be dragged from the icon.

Actual:
Tab does not respond to dragging from the icon until after it has loaded and drag is performed again.

Windows is more forgiving, allowing drag to work if the cursor is held still until after the loading animation finishes but this is not the case on Linux.

Vertical tabs in the collapsed state are especially affected since the icon dominates the draggable area. This is also the case with horizontal pinned tabs but they load on startup by default so are not normally affected. Rearranging many unloaded tabs requires "waking up" each tab first or dragging from the edges of the tab.

First appeared in version 57 when tabs changed to Photon design.

Regression window:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=52285ea5e54c73d3ed824544cef2ee3f195f05e6&tochange=63e261ce8cb04c913d2e6b19ea451b7078d24dc1

Possibly regressed by Bug 1349555.

Comment 3

[Kestrel]

Attachment: Dragging vertical tabs from icon fails when unloaded

Comment 4

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

:dao, since you are the author of the regressor, bug 1349555, could you take a look?

For more information, please visit BugBot documentation.

Comment 5

[Golden_Water]

Attachment: replace_children_after_mousedown_before_dragstart.html

with

<div id="parent" draggable="true">
   <div id="children">children</div>
</div>

it seems like if the "children" gets replaced between mousedown and dragstart, the drag would not start(when click inside children's display area), demo attached

I don't know if this is desired behavior, but in chromium the drag would start normally

for the issue of unloaded tabs, looks like it's setting tab label and icon when loading, leads to behavior described above

add pointer-events: none; to both .tab-icon-image and .tab-label-container seems fix it for tab

Comment 6

[Dão Gottwald [:dao]]

Moving this to Core based on comment 5.

Comment 7

[Sean Feng [:sefeng211]]

NI myself to take a look, I vaguely remember seeing something similar.

Comment 9

[Sean Feng [:sefeng211]]

So we prevent the drag from starting because the node is disconnected, hence this check fails. Maybe we should update the gesture content to the parent when that happens. I am trying to come up a patch.

Comment 10

[Sean Feng [:sefeng211]]

Attachment: Bug 1930931 - Make the dragging interaction still happens when the event target frame is moved/destroyed upon mousedown

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0294168d500c
Make the dragging interaction still happens when the event target frame is moved/destroyed upon mousedown r=masayuki,dom-core

Comment 12

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/50884 for changes under testing/web-platform/tests

Comment 13

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/0294168d500c

Comment 14

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

Since nightly and release are affected, beta will likely be affected too.
For more information, please visit BugBot documentation.

Comment 15

[Rares Doghi, Desktop QA]

Verified as fixed in our latest Nightly build 137.0a1 (2025-02-23)

Comment 16

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot