I haxed the Message Icon selection system to make it more usable. Instead of a single dropdown, all the icons are laid out onscreen. Click the icon to select it (its border will turn white; unselected icons have a black border). It works the same way as the previous Message Icons.
If anyone has any suggestions on how to improve how selected and deselected icons are indicated, please let me know. I'm pretty sure this selection system won't look any good on light-colored themes, e.g. Chaos Angel.