In https://forum.mendix.com/link/ideas/1105 Jan de Lange mentioned this problem: "The Ctrl-Click option for multi select has some limitations and if you select records and forget the ctrl button one time, you should start all over again."
Happens to #metoo occasionally: in a grid you select multiple lines by holding Ctrl-key and clicking on each record you want selected. Maybe you need to scroll down for the rest of the records and when clicking the next record, you forget to press Ctrl and you lost your selection. Start over. Hell, and I am quit certain that this happens to lots of users too.
That is a valid UI discomfort that can be solved by adding a "are you sure?" popup to warn you that you are losing your selection and giving you the option to keep your selection and add the last clicked record.
Therefor this idea: Add popup-warning to prevent losing your selection.
#metoo ctrl-click, especially when you need to go through quite a couple or look up something in between it's easy to forget pressing ctrl, maybe make the pop-up an option like there is for show empty rows yes/no, show pop-up before canceling multiselection yes/no