All potentially long operations should display a dialog with a cancel button.

[Freixas]

All potentially long operations should display a dialog with a cancel button. This should be part of your products' specification: when a potentially long operation occurs, the user should be informed by displaying a dialog (this seems to be what you do already) and the dialog should have a cancel button (this behavior is missing in at least one case).

Specifically, I noticed that the new Select Subject feature displayed a dialog letting me know it was working, so it's clear that you know this operation might take a while. However, the dialog has no cancel button.

I realize that there could be cases where a cancel button is not appropriate. In those case, a message that the operation cannot be cancelled should be displayed. Presumably, these cases would be the exception and not the norm.

I am suggesting that this feature be made part of your products' specification so that users don't have to explicitly request it for each slow operation. If a cancel button is left out, it could be reported as a bug, rather than requesting it as a feature.

[Bound by Beans]

Very much agree.