Try this way, start from the left hand corner of the chalk board and drag mouse down towards the bottom right hand corner this highlights it.......make sure you get it all
It should look like this
Then hit Copy
Then hit reply in normal way
At the top of the message board you will see the above, click on the one marked with the 2nd arrow it looks like a clip board........
this will paste the chalk board.
Then place curser inside the chalkboard where txt is and delete the old txt with the backspace on your keyboard then just type your message.