I wanted to edit and/or delete my synchronization connection under Central Administration –> Manage Service Applications –> User Profile Service Application –> Configure Synchronization Connections (under Synchronization) :
“Press F12 when you’re on the Configure Synchronization Connections page. This will fire up the IE dev toolbar, change Browser Mode to IE7. This will refresh your page and you will be able to use the dropdown menu.”
Thanks to Mark on the SP 2010 discussion forums for the quick response to this answer.