The Edit select tools should work the same as in other Esri products (like ArcGIS Pro), where you can add items to a selection using Shift+mouse and remove items using Ctrl+mouse.
Currently, you have to select more than one item initially before you can add to the selection, but this is using Ctrl+mouse.
The only way to remove items from the selection is clicking on them individually from the list. It's easier in some circumstances to remove a number of features using the mouse on the map.
It would also be helpful to flash the features on the map as you mouse over them in the list (and/or add a Flash capability in the Overflow options)
