2009006 - Expanding folder with many items takes long time (Firefox android)

Status: NEW

(Firefox for Android :: Bookmarks, defect)

Description

[artella.coding]

Steps to reproduce:

1)Move bookmarks

2)Expand folder with many items (8 subfolders + 450 bookmarks directly contained in folder)

Actual results:

It takes 24 seconds to expand folder

If I move the 450 bookmarks to a new subfolder, so that the folder being expanded contains 9 subfolders and 0 bookmarks directly within, expansion is very quick

Expected results:

Folder expansion should be quick since bookmarks are not displayed upon tree expansion.

Note I make use of tags and not sure if this is slowing things down, since each of the 450 bookmarks might have a tag associated with it.

Comment 1

[artella.coding]

The tree expansion referred to above is the new feature implemented by Add/Edit bookmark, change storage location: With extensive bookmark collections, the folder list loads extremely slowly. . The new feature is a great improvement over the previous implementation. Thank you very much.

Comment 2

[artella.coding]

Tree expansion of folders landed in Firefox for Android Nightly 148.0a1 (Build #20161 36535) on 07-Jan-2026

Comment 3

[Adina Petridean QA [:apetridean]]

@artella.coding, thank you for filing this issue.
I was not able to reproduce it on the latest Nightly (148.0a1) using a Google Pixel 10 (Android 16) and a Samsung Galaxy S23 Ultra (Android 14).
Could you please let us know which device and OS you were using when you encountered this issue?
If possible, please also share a screen recording. Thank you!

Comment 4

[artella.coding]

Attachment: nightly_move_tree_expansion.mp4

Hi Adina, thank you for cross checking. I have attached a video illustrating. Please let me know if it is not clear. Thanks

We see F2 has 2310 bookmarks
F3 has 6930 bookmarks

Still when moving bookmark opening F3 (in tree expansion) is very quick, but opening F2 is very slow

Comment 5

[artella.coding]

p.s. there is another bug that appeared at the same time as the above. Pressing back button on opened bookmark goes back to top level directory (in Nightly) rather than back to original directory containing bookmark (like in Beta)

Comment 6

[Denis Müller [:Webworkr]]

The problem of long loading times when expanding is mentioned, among other things, in Bug 1988315 ("Add/Edit bookmark, change storage location: With extensive bookmark collections, the folder list loads extremely slowly."), which I have therefore reopened. This may have overlapped in terms of timing.

Comment 7

[Denis Müller [:Webworkr]]

The bug regarding long loading times when expanding is now being tracked in this report.
See comment https://bugzilla.mozilla.org/show_bug.cgi?id=1988315#38.

Comment 8

[Denis Müller [:Webworkr]]

https://bugzilla.mozilla.org/show_bug.cgi?id=1988315#c38

Comment 9

[Denis Müller [:Webworkr]]

It would be desirable if not only a charging indicator were added, as suggested in Bug 1988315 comment 38, but also if performance could be improved.

Comment 10

[Denis Müller [:Webworkr]]

→ Bug 2011047 (Crash when adding/editing bookmarks, change storage location.)

Comment 11

[Denis Müller [:Webworkr]]

What is unusual is that different loading times are occasionally noticeable for the same folder.

Comment 12

[thehawaiiansteak]

i did some testing on a related bug where a bigger bookmark situation would turn it impossible to load at all and i think i might have found a clue on how this happens (unfortunately not the why)

im guessing this is happening because the folder attempts to read the bookmarks inside a folder as other folders, that sounds confusing so let me illustrate

📂 mobile bookmark

📁 folder A with 10000 unnested bookmarks
📁 folder B with 500 unnested bookmarks and 2 subfolders
📁 folder C with 12 subfolders that each has 5 subfolders and some that keeps on branching

the one that refuses to open is folder B, because firefox tries to load it as if it has 502 subfolders. folder A is a non issue because it doesn't have any subfolder to open, it only attempts to load a folder when you press the button, and only whats directly under it, which is also why after i emptied the unnested bookmarks in mobile i can load it just fine even though the problematic folder B is inside it

i have 0 clue on programming or anything of the sort though so take this with a grain of salt but i hope this helps!

Comment 13

[Denis Müller [:Webworkr]]

Bug 2027726
Optional enable/disable/on-demand for the bookmark counter