how to show or hide filter dropdown in record type in appian

I think you'll need to provide a lot more information. Where are you hoping to show or hide it? Why? In what cases would you show it and in what cases would you hide it?

This is  all filters on dashboard  I want to hide dropdown of "request release date" and after selection in request type dropdown "request release date" dropdown should be shown.  Dashboard is build in record type not in interface. So how to do that in record type.

In brief if I select one dropdown that will  make to appear two more filters, in normal view we don't see that two filter.

There is no means of linking Record User Filters in the way you describe. To do this you'd have to make your own custom solution that implements the Filters, controls the visibility between them (and/or the subset of their content depending on what is picked in any given filter) and then use the selected values to call a Query Record expression using those values, and then display the result-set in a custom grid.

There is no means of linking Record User Filters in the way you describe. To do this you'd have to make your own custom solution that implements the Filters, controls the visibility between them (and/or the subset of their content depending on what is picked in any given filter) and then use the selected values to call a Query Record expression using those values, and then display the result-set in a custom grid.

I build similar kind in interface, so what I understand in record type its not possible. its only possible in interface.