423cc678c8
Stores the currently open (right-click) menu in MyTreeView and adds a `close_menu()` method so inheritants can cleanly close the menu again if the context it was opened upon has changed. This is utilized by `AddressList` and `UTXOList` to close the menu if a call to `update()` has chenged the address list in some way or removed a utxo from the list to prevent the user from trying to use a utxo that doesn't exist anymore. Fixes #10464