My forum was converted from vBulletin to XenForo. I have a problem when editing users in Admin control panel. At first, this problem did not happen though. When I edit primary group or additional group of a user, the page keeps loading after I click save. It keeps loading for a while, and then nothing happens. After that, it will work when I click the save button again. Sometimes I have to click and wait for 3 - 4 times. Anyone knows how to fix this problem? Please help me.