On MW 1.24 Vector skin, with the user preference ticked or unticked, the sidebar still has items collapsible. The $wgVectorFeatures set to true or false only makes the option come and go from preferences, not enable or disable the collapsible items in the sidebar.
This was reported at http://www.mediawiki.org/wiki/Thread:Extension_talk:CollapsibleVector/Preferences_unticked
The error is probly in CollapsibleVector.php and CollapsibleVector.hooks.php Since global and user and selected as true.
I might have found a fix and will be uploading the patch later to be tried and if it succeeds in working I will then +2 it.
Change 177608 had a related patch set uploaded (by Paladox):
Fixes for CollapsibleVector
I have now uploaded the patch please could some review it to see if the change fixes this issue. I have tested it but I need someone else to verify that it fixes it.
Change 177609 had a related patch set uploaded (by Paladox):
Fixes for CollapsibleVector
It's the same with 0.1.3. Ticked or unticked, the sidebar still has items collapsible.
Also with CollapsibleVector commented out in LocalSettings.php UserMerge 1.9.0 still gives "Fatal error: Function name must be a string in ..../w/extensions/UserMerge/MergeUser.php". It's deleting the user page (on this wiki it gets created by the user registering) that allows merge and delete to function.
Hi if you download the patch. see if that works. it should put a tick in the check box it did it for me.
I will +2 it for you to try. if it cuasing more errors please tell here and I will then revert it. thanks for spotting this problem.
I've also tried the patch for usermerge (in version it shows as 1.9.0 (f1d6d58)) but the tick in preferences still has no effect.
Try earing your cache I have enabled it to do it global and in your preference it should show that it is ticked if not tick it and untick it and then clear cache see if that works. If not I will have to see why it doesn't work. Because the patch works for me.