Inbound Message Layout Fix

A long string of unbroken text (no spaces, like, for example, a Captcha response) will cause the Fields table (.postbox table.widefat) to expand beyond its parent container (#poststuff .inside), as shown in this linked screenshot.

This CSS seems to fix it for me:

table.message-fields td.field-value { 
    word-break:break-word;
}