A large text in received and sent PM represents incorrectly.

A larg text consists of, for example, 32 lines/144 words/980 letters goes beyond at the bottom of the text field.

How to reproduce:
1. Open and login forum.
2. Create a new PM, fill correctly To and Subject fields.
3. Message content field fill with a text wich consists of a big amount of lines (at least 30 and even more).
4. Send it.
5. Open sent PM in your Outbox.

AR: a text goes beyond at the bottom of the Message content field. There isn't a scrollbar in the Message content field.
ER: all text is inside of Message content field. There is a scrollbar there.
NOTE: in Drafts folder saved letters with a large text represent correctly.