Error message

[Madeline Harris]

Hello
 
I have received the following error message:
 
This transaction is already being edited in another register. Please finish
editing it there first.
 
The message was received when I pressed enter to record a transaction. I had
started to enter a transaction which I then decided I needed to split. I
can't remember the sequence of events after this, but now I can't add any
new transactions to this account. How can I find which other register is
being used? What can I do next? 
 
Thanks for your help.
 
Madeline Harris
(novice GnuCash user)