When Cyberduck exits due to crash or is terminated by user while non-responsive, don't show the donation nag.

[jlinBE]

Is your feature request related to a problem? Please describe.
Cyberduck crashes with some regularity. I don't think it's a good idea to show the donation nag when that happens.

[dkocher]

When the donation prompt is shown the application apparently did not crash. Also when force quitting the application it should not be possible the donation prompt is shown. What do you refer to by

crashes with some regularity

[AliveDevil]

We've finally found why Cyberduck sometimes stops responding to user interaction, when dialogs were shown with too much content: #17190
When triggering this behavior it's possible to close Cyberduck and get the donation prompt, even though it looks like it has "crashed".
Please check whether you're still seeing this behavior in 9.1.7