DisableDirtyOnBatch
From Foxmarks Wiki
If you find that Foxmarks often thinks it has changes to sync even when you haven't made any changes, this page describes a work-around that is available starting with version Foxmarks 2.0.45. Note that this is applicable only to Firefox 2, and if you use the bookmark manager to move or delete 5 or more bookmarks at one time, Foxmarks will not immediately detect this change if you make this setting. Your changes will sync the next time a sync occurs (manual or automatic), but an immediate sync will not be scheduled.
- Enter about:config in the address bar at the top of your browser.
- Right click (ctrl-click on the Mac) to open the context menu.
- Select New -> Boolean.
- Enter foxmarks.disableDirtyOnBatch as the preference name.
- Select true as the value.
This should resolve the problem, with the caveat mentioned above.
