Can't edit Main menu block in sidebar by clicking on "gear" Today on one of my websites I encountered something strange. I have my "Main menu" block in my left sidebar, and when I hover over that block, the "gear" to edit it shows up, but clicking on it does nothing. Also, on pages that the block wouldn't show up on, it does (rather, the blank space does) with nothing in it, and the gear still shows up and is not clickable. 

I tried moving the block out of the region, saving, refreshing, moving it back, saving, and refreshing again to see if that would fix anything, but that has not.

Any help would be greatly appreciated!

Updates:


What I mean by "nothing" is that there is the empty region with my main content area pushed over as if there actually was block content there. 
And 3 errors in the console: Uncaught TypeError: Cannot read property 'msie' of undefined panels.js?ndi45m:6.... Uncaught TypeError: Cannot read property 'msie' of undefined admin_menu.js?ndi45m:223.... Failed to load resource: net::ERR_CACHE_MISS
It is caused by legacy functionality in old versions of jQuery no longer being supported in more modern versions. In this particular case I think it has to do with browser version detection, which has fallen out of favour for feature detection. 

Add the jquery-migrate script to your theme's javascript folder and load it via your theme's info file.

If you continue to have issues you might need to make sure this file loads directly after the jQuery main file.