Neither of the previous replies did exactly what I wanted to do, but José's link did get me looking in a direction where I found a solution. I changed my listing so that the value I needed in the URL was the first column in the listing, then able to add a control to my widget with the action set to "New Window", filled the URL box with the URL but putting $$$VALUELIST where I needed that value to be, and set the "Active When" drop down to "1 Listing Item Selected". I set the Type to "Button" and gave it a label.

Now when you view listings in this dashboard and select one, you can click that button at the top to navigate where you need to go. That works for my purposes!