File-Preferences-Mail-Sending and Receiving (Alerts) is set to 'Slide in a summary'
(this is a sop to ex-Outlook users who can't or won't cope with noticing an icon in their taskbar)
Summaries slide in from the rightmost lower corner
When working with two monitors, it doesn't slide in on the rightmost corner of the screen in which Notes is maximised, rather on the rightmost screen - pretty useless if you work in Notes on the left screen
This would not be an issue if you could move the slide-in and let its location be sticky
So, PLEASE make the slide-in location sticky - let users put it where they want and let it stay there