/*
* Don't display tabs in mail (3-pane) window
*/
.tabmail-strip
{ display: none !important
}
Alternately, if there are always several browser tabs, "Edit => Preferences => Browser => Tabbed browsing => Hide the tab bar when only one tab is open" will hide the (single) mailer tab but not the (multiple) browser tabs. Not an obvious place to look for when trying to customize the mailer's display.
Of course, Thunderbird doesn't have this problem since it lacks the "suite" concept.
2009-09-02 10:47