PG down unnatural behaviour + customizable kb shortcuts?

[jtagcat]

RainLoop version, browser, OS:
Using Migadu, Latest Firefox and Ubuntu 18.04
Expected behavior and actual behavior:
go trough the list of messages with arrow keys, press pg down to scroll message, actually switches message.
I get the switch focus thing, but switching focus isn't practical. I propose pgdown/up always scrolls email and/or add support to let the user reassign kb shortcuts.

[jtagcat]

also: add an undo button/kb shortcut for taking back moving mail