User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:32.0) Gecko/20100101 Firefox/32.0 (Beta/Release) Build ID: 20140719074640 Steps to reproduce: I have firefox sync enabled for bookmarks. Windows 7. I went to my bookmarks menu to organize my bookmarks. "Show all bookmarks" selected. I have 22 main folders with approximately 2-10 subfolders, and some sub folders within those folders. Possibly up to 5000 bookmarks. I have had this problem several times. I noticed no similar bugs on bugzilla however this thread - https://support.mozilla.org/en-US/questions/947692 - seems to indicated that I am not the only one with this issue. I'm glad I finally took the time to try to figure out the root cause of this. Actual results: Created a new folder, selecting and dragging bookmarks into a folder or otherwise editing/changing bookmarks in some way causes significant lag for the UX to be responsive. Clicking a different folder and forcing firefox to come back to folder where changes occurred sometimes results in firefox showing changes faster than waiting for the UX to update itself. Expected results: Disabling Firefox sync of bookmarks completely eliminates the lag. Should not be necessary to disable a feature to re-enable basic functionality of the software: organizing bookmarks.

Additionally this Mozilla support post seems to indicate the same problem - https://support.mozilla.org/en-US/questions/975538 Additionally I would like to state that this issue has existed through the last few firefox versions and seems to have gone unnoticed.

I have the same problem here. I have thousands of bookmarks, and whenever I add, modify or exclude any bookmark, the bookmarks list freezes for a few moments. I believe this short freezing is related to Sync and the large number of bookmarks. If Sync is disabled, the freeze does not occur.

I can confirm that I've been experiencing this for ages, on both Windows and OSX. It makes managing bookmarks unbearable, with a delay of no less than 5 seconds for every bookmark change--be it renaming a bookmark, deleting, or moving one into a folder. I have disabled sync for bookmarks to overcome this in the past, and then enabled it when done, but that sometimes results in the bookmarks coming back, and other janky, unpredictable behaviour, so I've had to keep it enabled and just accept that cleaning up bookmarks is going to be an unnecessarily lengthy chore every time, due to having to wait so long between every insignificant modification.

This is because each bookmark change triggers a sync.

(In reply to Richard Newman [:rnewman] from comment #4) > This is because each bookmark change triggers a sync. OK, but in Chrome these freezes do not occur during synchronization. I'm not a developer, so I have no arguments, but the synchronization could not occur in another thread, or in "background", or when there were "resources" enough, or when Firefox was idle, etc?

Yes, you're exactly right, and the linked Bug 626279 is about fixing it to work more "in the background" in the way that you describe.

(In reply to Ryan Kelly [:rfkelly] from comment #6) > Yes, you're exactly right, and the linked Bug 626279 is about fixing it to > work more "in the background" in the way that you describe. OK, thanks for the reply!