1946548 - Thunderbird changes line spacing in message list and folder pane

Status: RESOLVED FIXED

(Thunderbird :: Folder and Message Lists, defect, P1)

Description

[David McDivitt]

Attachment: 2025-02-06 13_52_58-_save - local - Mozilla Thunderbird Beta.jpg

I just updated to TB version 136.0b1 (64-bit) on Windows 11 and my message list has unwanted spacing. I clicked around in options and have no idea how to remove the extra spacing. I want the rows immediately together like they were before this update.

Comment 1

[David McDivitt]

edit: falsely reported, did not change folder settings and columns displayed, only the line spacing was changed

---

This version also reset all my folder settings and what columns are displayed. Probably I can fix this. The glitch is the update process should not change UI settings.

I'm going to restore back to successive previous versions and my email folder until I see what version does this.

Comment 2

[David McDivitt]

I updated my email folder from last night's backup then reinstalled 135.0b4. Upon opening TB the message list appearance issue was not present. To validate I restored from backup again and installed 136.0b1 again. This time the message list appearance was not changed. It would be impossible to find the cause for this issue since updating to 136.0b1 a second time worked ok. Maybe do a brief review over what happens when doing an update any any changes.

Comment 3

[Magnus Melin [:mkmelin]]

I don't think any of that was deliberate no. Probably the file holding such settings was damaged so you got "default settings" instead.
FWIW, the spacing can be adjusted through App-Menu | Density.

Comment 4

[David McDivitt]

edit: spacing in the list of folders in the folder pane is also increased

---

The line spacing problem is back. I opened TB this morning and lines in the message list have spacing. This was not present before I closed TB last night. All I did was close TB last night and open again this morning.

I do think it's a bug in this version of TB: 136.0b1 (64-bit). I've never had this problem before and this is the second time when using this version that my message list line spacing changed.

This is a severe annoyance. I will however stay with this version because I prefer staying current. Someone please suggest what to change to remove extra spacing in the message list.

Comment 5

[David McDivitt]

(In reply to Magnus Melin [:mkmelin] from comment #3)

I don't think any of that was deliberate no. Probably the file holding such settings was damaged so you got "default settings" instead.
FWIW, the spacing can be adjusted through App-Menu | Density.

I don't know where / App-Menu | Density / is.

Comment 6

[David McDivitt]

The extra spacing is present in dropdowns, too, such as when moving a message to another folder all the folders listed have increased spacing.

Comment 7

[David McDivitt]

I just did the following:

1. Opened TB and observed extra spacing in the message list and folder list
2. Closed TB
3. Deleted compatibility.ini
4. Installed 135.0b4 (64-bit) replacing 136.0b1 (64-bit)
5. Opened TB and observed extra spacing WAS NOT PRESENT in the message list and folder list
6. Updated to 136.0b1 (64-bit) through help/about
7. Upon reload extra spacing WAS NOT PRESENT

I will leave things this way and repeat steps 3 & 4 if needed and post if 136.0b1 (64-bit) messes up my message list again.

Comment 8

[David McDivitt]

Again:

1. I had TB open from the previous comment posted here. Extra spacing was not present in the message list.
2. Closed TB.
3. Opened TB and extra spacing was present in the message list.

To me this seems a good isolation of a bug present in 136.0b1 (64-bit).

I'm going to install 135.0b4 (64-bit) again then occasionally try updating again to see if the problem has gone away, backing up my email folder each time.

Comment 9

[Alessandro Castellani [:aleca]]

I think I found the issue.
It seems that this calculation is wrong after the second restart: https://searchfox.org/comm-central/rev/7952487cd298e5db953c2c630f53d56a2541e012/mail/modules/UIFontSize.sys.mjs#139-141

STR on Windows with trunk:

• Compile Thunderbird and launch it without any font size change.
• Everything should look good and the default font size should be 12px (this changes based on your OS settings, mine is 12px on Windows 11 with HiDPI).
• Close and relaunch without compiling.
• The default font size is now reported as 17px!!!

The actual OS font size is 12px even if the computed style reports it at 17px.
So Thunderbird has the correct font but all the height calculations use an incorrect (larger) font.

Temporary workaround.
Update the font size to the value you want. If I manually set my font size to 12px it's the maintained after the restart and the height calculation is correct.
This is only temporary since the default font size is still incorrectly reported as 17px.

Questions:

• Did something changed in toolkit about getComputedStyle() or documentElement?
• Why on first run after compile the font size is correct but after restart is wrong?
• Is this a Windows only issue>

Pinging a few folks to get some help and point of views.

Comment 10

[Alessandro Castellani [:aleca]]

Attachment: Screenshot 2025-02-10 125901.png

Even more interesting is the fact that in the console on runtime the reported font size is correct (12px), even tho the startup font size is not (17px).
Race condition?

Comment 11

[Alessandro Castellani [:aleca]]

Confirmed that this is probably a race condition.
If I add a 100ms timeout to that getComputedStyle() I always get the correct font size.

Comment 12

[Emilio Cobos Álvarez (:emilio)]

Are you querying the computed style before the relevant stylesheets load? That would trivially cause what you're describing.

Comment 13

[Alessandro Castellani [:aleca]]

(In reply to Emilio Cobos Álvarez (:emilio) from comment #12)

Are you querying the computed style before the relevant stylesheets load? That would trivially cause what you're describing.

How do I see that?
We had this font size feature since 115 and it started failing since 136 alpha.
We always connected the font size calculation to the DOMContentLoaded event.

Comment 14

[Alessandro Castellani [:aleca]]

Found the regression!
Bug 1916066 is registering the window before the onload event and is making a mess of everything.
https://searchfox.org/comm-central/rev/7952487cd298e5db953c2c630f53d56a2541e012/calendar/base/content/calendar-ui-utils.js#21

I have a fix for it.

Comment 15

[Alessandro Castellani [:aleca]]

Attachment: Bug 1946548 - Update incorrectly registered windows in UIFontSize. r=#thunderbird-reviewers

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/377e71ebd9ea
Update incorrectly registered windows in UIFontSize. r=freaktechnik

Comment 17

[Corey Bryant]

Thunderbird 136.0b2:
https://hg.mozilla.org/releases/comm-beta/rev/783dbd11b07f

Comment 18

[Corey Bryant]

Approval request is not working on this bug for some reason.
[User impact if declined]
Broken UI spacing for message list with default font size.

[Is this code covered by automated tests?]
No

[Has the fix been verified in Daily? (or Beta for an ESR uplift?)]
Fixed on Daily and verified by core devs

[Needs manual test from QA?]
No

[List of other uplifts needed]
None

[Risk to taking this patch]
Low

Comment 19

[Corey Bryant]

Approval not working but this is uplifted!

[Triage Comment]
Approved for beta