One way to do it is go to Activity -> Jobs which will show you the recent searches.
Are you wanting to see the query dynamically within the dashboard for people using it OR are you asking more from a troubleshooting perspective? For troubleshooting what I tend to do is adjust my inputs in order to get the query to run and then click the magnifying glass in the lower left corner of the dashboard panel. That opens the query into another browser tab and allows me to see what Splunk is trying to run.
I like this answer too!
One way to do it is go to Activity -> Jobs which will show you the recent searches.
You can check the actual query ran in Job Inspector. It is present in Search Properties under eventSearch