Hello Technuts,
On Patrick's sheet the dropdown picks up all locations shown in Places. Places is a named range which is defined as =Sheet3!$A$2:$A$6
If you add some locations, e.g. down to A10 then if you change the definition of the named range these will automatically appear in the dropdowns. To do that
Insert > Name > Define
click on places and change the definition in the "refers to" box to
=Sheet3!$A$2:$A$10