Which Umbraco version are you using? (Please write the exact version, example: 10.1.0)
14.2.0
Bug summary
When using the Multi Url Picker data type and you are adding a single link, you are able to select something in the content tree at the same time as selecting something from the media tree.

Specifics
See above
Steps to reproduce
Install 14.2.0
Add a multi url picker property to a doc type
try to edit the property and select something from the content tree at the same time as some thing from the media tree
Expected result / actual result
When you pick something from the content tree it should unselect whatever else you picked even if it was in the media tree and vice versa.