Hotkeys on operations would be great, configurable ones will be even better.

Currently, the "delete" animation is far too slow for fluent. Please consider speeding them up significantly.

Currently, the mail groups appear in the style of one per column. This could be a terrible waste of screen space, especially if there is a huge amount of groups with only one mail under them. Please consider fitting more groups under one column.

Please adapt the search bar according to the screen space available. (This one should be easy)