How can I select first value of the dropdown by default in Palantir Foundry Workshop?

I have a string dropdown populated by a variable in Workshop. I would like the dropdown to select the first value by default when the underlying set recomputes. How could I do that?

In a case like this, you have 3 object sets (one of which is the currently-selected object), plus whatever changes the "input" object set. In my example below this is a filter, but it could be a function, the result of some user interaction, etc.

• (BLUE) Object Set that is your starting object set. In the example below I'm using a Rides object type (e.g. in a theme park) and this object set is defined simply as all Rides. In my example this is the "OBJECT SET" to the filter widget config panel.
• (GREEN) Object Set that is the input to the dropdown. This is the one that's affected by filter I describe below. To create it, I started with all Rides (BLUE) and applied a filter variable (YELLOW). If, for example, you're using a function instead of a filter to change the object set, then this object set would be the one returned from the function. This is the "INPUT OBJECT SET" for the Dropdown widget config panel.
• (RED) The selected object in the dropdown. When you add the widget, this is created automatically for you. In my example, I renamed this variable. This is the "SELECTED OBJECT" in the filter widget config panel.
• (YELLOW) Filter Output. Again, this is specific to my example. Maybe in your situation there's a function that changes the object set that's in the dropdown menu. This is the "FILTER OUTPUT" for the filter widget config panel.

Conceptually, what's happening here is:

1. The Filter widget takes (BLUE) Object Set as its input and returns a (YELLOW) Filter Output.
2. (YELLOW) Filter Output is used to construct a new (GREEN) Object Set.
3. (GREEN) Object Set is used as input to the dropdown.
4. (RED) selected object in the dropdown will update whenever the (GREEN) object set updates.