To tag a dropdown as a feature
1. Got to app.pendo.io/features and press the "manage features in-app" button in the top right hand side of the page.
2. When the designer is loaded, click tag feature and press ALT(Windows)/Option(Mac) while clicking on the dropdown to expand it.
3. Then you will be able to click on the element needed (depress ALT/Option)
If you have tagged the element but are not seeing any click events, check to see if that dropdown is coded using <option> HTML elements. If they using <option> and <select> elements then tagging them as features within Pendo is not currently possible.
However, you could still track these interactions with a track event. You can read more about track events and configuration here.
If you're still not sure if your dropdown uses <option> elements, you can check by right clicking on that element and selecting "inspect." The browser developer tools will load and you will see a section of highlighted code - check for the words option and select. You can also see a sample of this code here.