You can turn on the test mode to check inactive recommendation boxes on you site safely. To turn it on, go to the main menu "integration" and the sub-menu also called "integration" and scroll down to the "testing" section. Here you can turn on/off the test mode.
The test mode is turned on/off only for your current browser in which you are using the Dash. If the test mode is turned on successfully you will see a small notification in the upper left corner of you site.