Wildcard as Variable for Input box / Set Analysis

[ksharpes]

I have a variable called v_CoverageGroup set to ''Short', 'Med', 'Long', 'Very Long'' by default.

This shows all of the desired selections for a set analysis I have done.

I have an input box so I can select each of the selections one at a time however I cannot put ''Short', 'Med', 'Long', 'Very Long'' as an option as it refuses to accept the syntax.

to get around this is there a way to have a selection use the default value? or perhaps a way of clearing the selections instead?

OK well it appears my Default variable does not seem to working correctly either, Would it be possible to have a wildcard instead and show all values?

[treysmithdev]

My favorite extension for this functionality is SimpleFieldSelect.

[ksharpes]

Thanks, although that doesn't get over the issue I'm having 

My Code is as follows:Sum({<[Reporting Date]={'$(=monthend(MAX([Reporting Date]),-6))'},[Coverage Group (All)]= {'$(=v_CoverageGroup)'}>}[Stock Value €])

My Variable (v_CoverageGroup) has values of Short, Med, Long & Very Long

How can create a variable that has all four values that still works?