Summary:

The Subject line and the From: field do not get cleared when an email template is removed when writing a new email

Symptoms:

If a template is selected in a new email that contains text in the subject line and then the empty (blank) template is selected, the from: box and the subject line from previous template remains.

Status:

This issue has been addressed and fixed in 2015 R1 which is due for release in May 2015