I noticed today that the Icon manger, when opened, only displays a blank dialog box. I can no long upload a custom icon.
Change Icon > Manage Icons
Seems to be working fine for me? You must click the “plus” icon in the bottom left of the “Manage Icons” window and add your custom icons. Then they appear in the normal list of icons in the context menu.
(Using RC2)
Maybe try doing a full uninstall and reinstall to get problems of that nature out of the way. If you’ve been incrementally upgrading over a long period of time, it could be an error crept in.