Be careful with the close box, it's a cancel
On the expander bar there is a little Close button, a circled-x which only appears in the Expanded view.
This is part of the standard iMessage interface so Touchgram cannot do anything about it.
Be very careful about hitting this Close.
The close will cancel the current message you are editing and drop you back into the normal Transcript view of iMessage.
However, Touchgram remembers where you were at. If you were in the middle of editing a message, the draft you'd created is remembered for this conversation. When you go back into Touchgram, what you created will be there for you.
Note: a fun fact from the early development of Touchgram - we weren't going to cope with this until later. None of the other complex iMessage apps did anything smart - they just lost your message if you accidentally tapped the Close button. As the founder's wife was a beta tester, she was rather upset about losing a Touchgram she'd been working on and insisted that version 1 of Touchgram coped with the close. That's why, from the beginning, Touchgram remembers what you're working on.