Please describe the problem:
if i create a new mail, i insert the recipients, press tab to jump to the subject line, insert the subject, and pres tab again to jump to the content field. now i recognize that i am not at the first position. there is a tab inserted into the content field.

Steps to reproduce:


Actual results:


Expected results:


Does this happen every time?
yes, since 2.8.*

Other information:
if i click into the content field to focus it, there is no tab inserted.
it happens only with pressing tab to focus this field.