Search within column - Limiting values in Property Control

Before we begin, I have a question. Why List Box filter is so special ?

Yes, you got it right! The search within column values. What if we want to implement something similar for List Box Property Control ?
We are going to do it today !!
Let's Start.

1. We are going to create a Input Field property first to capture our search string. In this example, I am going to call it - ${CountrySearch}. This is going to search values in [Country Name] column.
2. Create a Calculated column [Country] to hold search results with expression below -If(Len('${CountrySearch}')>0,
        If(Find(Lower('${CountrySearch}'),Lower([Country Name]))>0,
                [Country Name]) ,
        [Country Name])
3. Now create your Property Control using column [Country]. I have given a search button, just to move focus out of search box; however hitting enter also works well.

Here is what we have in the end -