While most features display function as they do on a published site.  One element that can not be tested in the preview our build mode is buttons. 

Clicking on the button will open it to the edit mode. In some cases this can reset that data even if not changes are made.

The best way to test a button is to publish your Folio. Once published open the Folio URL in a new browser tab and test your button function.

Note: On a traditional browser the call feature may not work, email function on a traditional browser will open an email program if you have set your browser to do so for mailto: style links.