10.8. Enigmail icons in the toolbar are misaligned

If you're using SeaMonkey and your toolbar looks like:

then try changing your theme twice. If you are using the Modern theme as in the picture, switch to the Classic theme and quit SeaMonkey. Restart, change back to the Modern theme, quit, and restart again.

If you're using Thunderbird, then your theme does not contain the necessary icons for Enigmail. Please report the problem to the author of your theme.