I would suggest listing that in the Filter function itself. Something like:
SortByColumns(Filter([@'Table'], StartsWith(Title, TextSearchBox1.Text), IsBlank(Dropdown1.Selected) || Column1 = Dropdown1.Selected), "Date", If(SortDescending1, Descending, Ascending))
You might have to so Dropdown1.Selected.Column or Selected.Value depending on how you have the dropdown defined. You would also have to replace Column1 with the name column of your choice. The formula will need to.be modified slightly if you are using a combo box (with multiselect) instead of a dropdown.
Let me know if this helps.
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Thanks!
Hardit Bhatia
The Power Addict
https://thepoweraddict.com