"Computing your transaction" popup stays open when there is a tx error

[leto]

I was doing a z => t transaction and I had insufficient funds (an error that should be checked way earlier) and it gave me a popup error about it. When I accepted that, the animated gif window of "Computing tx" stays open and the user must close it themselves.

This is not critical but an annoyance as it makes the user do another action for no good reason.

The window should be automatically closed before we pop up the window saying what the error is.