Crash when closing score with empty text-frame

Steps:
1- Launch MuseScore and open a score, e.g. My_First_Score;
2- Select one measure (e.g. the first measure);
3- Add -> Frames -> Insert Text Frame;
4- Click outside the text frame without typing anything;
5- Close the score and discard the changes -> crash.

Windows 8.1 & Linux MInt 17.1, commit 11b49de3e7

Attached address sanitizer log.