Queries :: Using Variable In A List Field Query - Getting Complete List On Initial View

In my access form I provide the user a list of locations from various countries in a listbox . But the list is too long so I provide him a combobox for selecting a country. Selecting the country should update the listbox showing only the locations in that specific country.

So my SELECT from the listbox must cover the unselected state and show all entries and when a country is selected it must narrow the selection.

I tried to get this happen with the following SELECT statement containing a variable. Choosing a country in the Combobox results in a change of the variable and in a requery. This works after the first country is selected and for each country change, but the initial list is empty.

VBA in the loadform
'Application.TempVars.Add "varcountryselect", "*"
SELECT in the listbox "lstlocationsperproject"
SELECT tbllocations.locationID, tbllocations.country, tbllocations.localstreet, tbllocations.localcity FROM tbllocations WHERE ((tbllocations.country) Like [TempVar]![varcountryselect]);

VBA in the combobox
Application.TempVars("varcountryselect") = [Form]![kombcountryselect].Column(0)
Me.lstlocationsperproject.Requery

The values in [kombcountryselect].Column(0) are texts like "SPAIN", "MEXICO", etc.

Any hints, how I have to use the * for getting the complete list on the initial view ?