From Bug 274561.
I tested Bug 274561 case(same problem when To: header)
> To: =?iso-8859-1?Q?Fa=2E_St=FCrtz=2C_Engel?= <email address hidden>
And problem was re-created.
Then I tested escaped "," case.
> To: =?iso-8859-1?Q?Fa=2E_St=FCrtz=5C=2C_Engel?= <email address hidden>
- "\"(=5C,escape char) is inserted before ","(=2C)
Although another problem occured in this test,
- Display becomes Fa. Stürtz\\, Engel
Special data was displayed(escape char in this case).
This is already reported problem.
problem of this bug was resolved.
Mozilla handled "," correctly when "," was escaped before encoding.
Sorry but I'm not familiar with Quoted Printable, so I don't know whether result
of inserting "=5C" only is valid QP or not.
And I can not say RFC 2822's spec is which, "," in atom should be escaped before
encoding, or no need to escape.
From Bug 274561. 1?Q?Fa= 2E_St=FCrtz= 2C_Engel? = <email address hidden> 1?Q?Fa= 2E_St=FCrtz= 5C=2C_Engel? = <email address hidden>
I tested Bug 274561 case(same problem when To: header)
> To: =?iso-8859-
And problem was re-created.
Then I tested escaped "," case.
> To: =?iso-8859-
- "\"(=5C,escape char) is inserted before ","(=2C)
Although another problem occured in this test,
- Display becomes Fa. Stürtz\\, Engel
Special data was displayed(escape char in this case).
This is already reported problem.
problem of this bug was resolved.
Mozilla handled "," correctly when "," was escaped before encoding.
Sorry but I'm not familiar with Quoted Printable, so I don't know whether result
of inserting "=5C" only is valid QP or not.
And I can not say RFC 2822's spec is which, "," in atom should be escaped before
encoding, or no need to escape.