The "Manage search engines..." menu for the omnibox settings seems to have some bugs. I tried to delete the default ones listed and add Duck Duck Go as my new default. I did this part successfully, however, shortly afterwards I realized I had set the wrong search URL for the Duck Duck Go entry. When I went back to fix it, not only had it reverted the Duck Duck Go URL to an AOL search query URL, but I also now can't change my default OR add any new entries. I.E. I tried both a) overriding the AOL URL in the Duck Duck Go entry with the correct Duck Duck Go entry, and it simply refuses to take it--the AOL URL seems to be permanently associated, and b) re-adding Duck Duck Go as a new entry, but it no longer even has the option available to the far right to "set as default" or even delete, add, anything. It just seems like it got all bugged out on me for no reason.
Any solution for this? As it stands now, I'm stuck with ONLY AOL as an omnibox option, and I can't do anything else anymore. Dead in the water here.