Beware of Horde’s IMP webmail client and its access/shortcut keys.
One that’s caught me is that if new email composition is set to be in a separate window, and access keys are on, then Alt-F4 (which in Windows is normally the equivalent of Close) is pressed, instead of saving the email to Drafts, or cancelling the email, it sends it.
I’m a common user of Alt-F4, which means several times I’ve thought I was cancelling the email, but instead it’s sent it.
Another is Alt-D for Delete (the current message). On many browsers this predates Ctrl-L to go to the address window, and while I know I should learn Ctrl-L, I still commonly press Alt-D. If Horde is configured to not even put the message into the Trash, carelessly pressing Alt-D will zap the message forever more, no trace left.
To prevent these happening again, I’ve now turned off Access keys: Options / Global options / Display Options / Should access keys be defined for most links?