redirect URL gets corrupted by TinyMCE

When working with TinyMCE enabled, the field "confirmation" (Confirmation message or redirect URL) in the webform edit form has TinyMCE enabled as well.

Even if one is not touching this field, TinyMCE takes the liberty to add a newline (^M) to the end of this field if it is not already there. When using an 'internal:' syntax, the redirected url becomes 'url^M', which obviously doesn't work.

Possible solutions:
1) Disabled tinyMCE in webforms - this has been discussed elsewhere in the site and is a valid solution. However, I still want to have TinyMCE enabled in the 'Description' part of this form, so it's not good enough for me.
2) Fix the TinyMCE module not to do evil
3) Use the attached (very simple) patch