1968250 - The "Move Tab to New Window" option should not be available if there's only one tab

Status: RESOLVED FIXED

(Firefox :: Tabbed Browser, defect, P3)

Description

[Ada C.]

Found in

• Nightly 140.0a1

Affected versions

• Firefox 139.0
• Nightly 140.0a1

Tested platforms

• Affected platforms: macOS 13 ARM

Steps to reproduce

1. Go to about:preferences#general
2. Enable "Vertical tabs" from Browser Layout
3. Have only one tab open in Sidebar
4. Right-click on the tab
5. Select "Move Tab" > "Move to New Window"

Expected result

• The "Move Tab" > "Move to New Window" option is disabled.

Actual result

• The "Move Tab" > "Move to New Window" option is not disabled.

Regression range

• Not sure if this is a regression. If there is one I will find it asap.

Comment 1

[Ada C.]

Attachment: Screenshot 2025-05-23 at 4.55.57 PM.png

Comment 2

[Timea Zsoldos [:tzsoldos], Desktop QA]

I investigated for regression range by running mozregression between 2025.05.13 and 2025.05.25, found the folllowing:
Last good revision: 50168e035edfe105d0a574e63947e8d0b35a0be9
First bad revision: e6cd6f4fb15b654b22c328f500d1699e8c04d28a
Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=50168e035edfe105d0a574e63947e8d0b35a0be9&tochange=e6cd6f4fb15b654b22c328f500d1699e8c04d28a
point to bug 1921835
Investigated on macOS 10.15, not reproduced on 138.0.4, 139.0 and 139.0b10.

Comment 3

[Donal Meehan [:dmeehan]]

Comment 0 mentions 139.0 is affected, but the regressor versions in Comment 2 indicate that only Fx140+ is affected.

Comment 4

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

:jswinarton, since you are the author of the regressor, bug 1921835, could you take a look?

For more information, please visit BugBot documentation.

Comment 5

[Donal Meehan [:dmeehan]]

Next week is the final week of beta for Fx140
:jswinarton, do you plan on having a patch in time and requesting a beta uplift?

Comment 6

[Jeremy Swinarton]

Hi :dmeehan, I have plans to investigate this but I am not sure I will have time before the beta uplift. I think it would be better to target this for 141.

Comment 7

[Pascal Chevrel:pascalc]

Jeremy, is 141 still a target? Thanks

Comment 8

[Jeremy Swinarton]

Hi Pascal, we have not had time to investigate this as part of this cycle. I am not sure we will have time until at least 143. I will raise this with our team in our next planning session.

Comment 9

[Stephen Thompson [:sthompson]]

Looks like it was indeed regressed by bug 1921835.

Code was patched to:

let visibleOrCollapsedTabs = gBrowser.tabs.filter(
  t => t.isOpen && !t.hidden
);
let allTabsSelected = visibleOrCollapsedTabs.every(t => t.multiselected);
contextMoveTabOptions.disabled = this.contextTab.hidden || allTabsSelected;

This used to call gBrowser.allTabsSelected() which has an explicit check for this.visibleTabs.length == 1.

Any fix for the "disable the menu option with one lone ungrouped tab in a window" case should also account for collapsed tab groups. If the tab strip has 1 collapsed tab group and 1 ungrouped tab, the ungrouped tab should still be allowed to move into a new window even though it is the only visible tab in this case.

Comment 10

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

This good-first-bug hasn't had any activity for 2 months, it is automatically unassigned.
For more information, please visit BugBot documentation.

Comment 11

[aaryamannsingh3]

(In reply to Stephen Thompson [:sthompson] from comment #9)

Looks like it was indeed regressed by bug 1921835.

Code was patched to:

let visibleOrCollapsedTabs = gBrowser.tabs.filter(
  t => t.isOpen && !t.hidden
);
let allTabsSelected = visibleOrCollapsedTabs.every(t => t.multiselected);
contextMoveTabOptions.disabled = this.contextTab.hidden || allTabsSelected;

This used to call gBrowser.allTabsSelected() which has an explicit check for this.visibleTabs.length == 1.

Any fix for the "disable the menu option with one lone ungrouped tab in a window" case should also account for collapsed tab groups. If the tab strip has 1 collapsed tab group and 1 ungrouped tab, the ungrouped tab should still be allowed to move into a new window even though it is the only visible tab in this case.

Looking into this bug

Comment 12

[aaryamannsingh3]

Attachment: Bug 1968250 - Add check for single tab in selected tabs calculation. r=#tabbrowser-reviewers,sthompson

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/8b01478d36a8
https://hg.mozilla.org/integration/autoland/rev/b9c93abfc0db
Add check for single tab in selected tabs calculation. r=sthompson,tabbrowser-reviewers

Comment 14

[Cristina Horotan [:chorotan]]

https://hg.mozilla.org/mozilla-central/rev/b9c93abfc0db

Comment 15

[Timea Zsoldos [:tzsoldos], Desktop QA]

Verified as fixed with nightly Firefox 149.0a1 (2026.02.05) on macOS 10.15, now The "Move Tab" > "Move to New Window" option is disabled, having only one tab opened in vertical sidebar.