Closed Bug 1824767 Opened 1 year ago Closed 1 year ago

Resizing message list column sometimes stubbornly reverts to original column width


(Thunderbird :: Mail Window Front End, defect)

Thunderbird 112


(thunderbird112 affected, thunderbird113 affected)

113 Branch
Tracking Status
thunderbird112 --- affected
thunderbird113 --- affected


(Reporter:, Assigned: darktrojan)


(Blocks 1 open bug)


(Whiteboard: [Supernova3p])


(2 files)

Attached video ScreenRecord.mp4

Steps to reproduce:

Maximize Thunderbird window on 1080p monitor.
(I'm using Windows 10 - See screen recording)
Try to shrink first column

Actual results:

The column width doesn't adjust as expected. Sometimes it adjusts slightly other times it reverts back to original width.

Expected results:

The column width should adjust to the location where the cursor was when the mouse button was released.
Other columns should be minimally affected.

Hey Meichthys, this works for me on Daily 113.0a1 (2023-03-27) (64-bit) and Beta 112.0b3 (64-bit), Win10, 1920x1080p (175% screen scaling I believe), using exactly your column layout (Attachments, From as first columns etc.) on Win10. It lags a little bit on fast mouse drags, but always ends up at mouse position and won't spring back, except in very narrow scenarios (Subject does seem to have a min-width).

So I'm not sure what's causing the behaviour for you. Any details you can add for reproduction?
Does this work for you in ≡ > Help > Troubleshoot Mode…?

Blocks: sn-msglist
Flags: needinfo?(
Whiteboard: [supernova]
Summary: Difficulty Resizing Columns → Resizing message list column sometimes stubbornly reverts to original column width

I am indeed using v112.0b3, Windows 10, and 1920x1080p resolution

  • Resolution is not the issue, I can reproduce it on different resolutions
  • Troubleshoot mode works flawlessly (Even without disabling add-ons or resetting toolbars/controls)
  • The columns in the Task section of the Today pane adjust perfectly fine regardless of troubleshooting mode
  • Restoring column order makes it work as well

After restoring column order, now I cannot re-arrange the columns (

Perhaps once the column ordering bug is fixed, then this issue will also be fixed.

Flags: needinfo?(

Also relevant: #1819104

I can reproduce the resizing issue on 113.0a1 Windows10 with new profile.


  1. Default columns are [Subject]s1[Correspondents]s2[Date]
    where s1, s2 denote the splitter.
  2. Drag s1 to the left so that [Subject] column will narrow
  3. Drag s2 to the right so that [Date] column will narrow
  4. Drag s1 to the right
    --- Observe the strange movements of the splitter.
  5. Mouseup
    --- Observe that the splitter jumps to the left.

Actual results
Strange movements of the splitter.
Splitter jumps to the left.

Expected results:
The splitter should follow the mouse pointer as it moves.

Ever confirmed: true

I think this is happening because you've got a non-resizeable column (the thread indicators) after the last resizeable column (the date). In this case the date column should not be resizeable (i.e. the right edge of it shouldn't be moveable) because that doesn't make any sense.

You can also re order columns via keyboard.
Click on the quick filter search bar and then press TAB until the focus reaches the table header.
Move the focus to the column header you want to move, and then press ALT + ArrowRight/Left to move them around.

This is a somewhat known issue alongside some other minor strange issues with the resizable columns.
This happens because there are widths set to some of the columns, while others are non resizable like the icon columns, and when TB goes full screen the table layout tries to automatically fill the available space, and in doing so it breaks out of some width limits of the non resizable columns, causing these glitches.
The problem is much more prominent with fewer visible columns and TB in full screen.

If you reorder those columns you should be able to mitigate the issue.
We will fix that later on.

Assignee: nobody → geoff
Target Milestone: --- → 113 Branch

Pushed by
Fix resizing of tree columns when followed by non-resizable columns. r=aleca

Closed: 1 year ago
Resolution: --- → FIXED
Regressions: 1826881
No longer regressions: 1826881
Whiteboard: [supernova] → [Supernova3p]
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