FF V17 - about:config - why after editing a line the cursor moves to the top or bottom of the entire list/
got affected line (like a dodgy toolbar), modify to remove contents. then the curser should move to the next line but as of FF 17 it moves to the top or bottom of the entire list.
Actually the cursor shouldn't move at all if you try to modify a pref on the about:config page.
So you may have a problem with an extension or theme.
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).
- Do not click the Reset button on the Safe mode start window or otherwise make changes.
This is another issue with FF V17. it doesn't display add-ons or plug in's just a blank page, so if I need to amend any plug in or add on, there isn't a way of doing this in V17. All was okay on V15.1.
It is possible that there is a problem with the file(s) that store the extensions registry.
Delete the files extensions.* (e.g. extensions.sqlite, extensions.ini, extensions.cache) and compatibility.ini in the Firefox profile folder to reset the extensions registry.
New files will be created when required.
See "Corrupt extension files":
If you see disabled, not compatible, extensions in "Tools > Add-ons > Extensions" then click the Tools button at the left side of the Search Bar (or click the "Find Updates" button in older Firefox versions) to check if there is a compatibility update available.
If this hasn't helped then also try to delete the addons.sqlite file.