Ok, how about this idea.
In the same way that when you password protect your wallet you're forced to reboot the QT, why not make it that once you press Start Mixing, a pop-up appears warning the user the QT needs to restart the wallet to prepare it for the mixing process, warning users to "Please backup after restarting"
"Creating mix wallet requires you to restart the QT. It's a one time operation and can take just a few minutes. Please backup wallet after restarting. Existing funds will not be affected, but previous backups will become obsolete" - sort of thing?
On close/reopen you could have it fill the keypool with an absurd amount. Also in the Information window there could be a keypool monitor, or even right under the Private Send amount in the main windows to help keep track ... when it is about to, or actually runs out (x<1000) it could warn the user to refill and backup again?
Ideas are easy, hum?
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