Basecamp Frustration - Unit item management

Hi folks.

Well, been editing POIs and entries in my GPSmap 62stc for a couple hours now. Been shoving POIs into the unit as proper POIs instead of waypoints, in order to save memory. Been trimming routes and tracks imported from various sources, down so that they too don't take up too much memory.

I keep deleting items using command-delete (Mac) but they don't want to go away. They keep coming back.

What am I doing wrong? I clean up my contents directly on the unit, but it doesn't go away.

Why is this so difficult? Am I missing something?

Any advice/insight appreciated. Would be nice if Garmin chimed up. Years using this software and it's as confusing as day one.

Thank you.

Cheers