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

Status: NEW

(Firefox :: Tabbed Browser, defect, P3)

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?

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