Be aware that if you move a *reference* to the trash it gets removed from all collections. To remove a reference from only a single collection (leaving its presence in other collections intact) then use "Remove Item from Collection…".
Thanks for this reminder. I have the same reference at the top level of a group and in a collection within the group. I'd like to remove it only from the top level. (I own the group.) As far as I can tell, "Remove from Collection" is not available for this particular maneuver.
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