Current Issue
Currently if you go to Receive / ... / List of Addresses the list doesn't contain addresses that are change addresses, therefore if you want to sign a message with an address you own which is a change address it will not be possible.
Expected Behaviour
If I open the List of Addresses screen, I should be able to see all the addresses I used whether it was generated manually generated for receiving or if it was autogenerated by the wallet to be a change address.