[SHIFT]+[DEL] works to permanently delete single messages, but when multiple emails are selected the emails just go to the trash as if I hadn't used [SHIFT]+[DEL]. I have not disabled the warning pop up which asks you to confirm that you really want to permanently delete the emails. I get this warning when there is only one message selected but not when multiple messages are selected. When I look at the trash I see that the selected emails are there instead of being immediately deleted. I am having this problem in Troubleshoot mode as well. This is in Linux on a Chromebook.