1. Start the DemoBench
2. Start the Notary, and two Nodes (Bank of Breakfast Tea and Bank of Big Apples)
3. Do a cash issue from one bank to another but enter a negative amount
When you do this you get a pop-up saying that the amount is invalid. However when pressing OK the Node Explorer dies. I believe a user would expect the pop up to close, but the Node Explorer to remain running so that a valid amount could be added.
Seen on MacOS, expected to be the same on other.