Mouse Click marker to display infowindow in placeholder on ‘MouseClick’ Event.To show infowindow you should do following steps :

Step 1: Go to Add or Edit Map and scroll down to ‘Infowindow Settings’ section.

Step 2: Point to ‘Show Infowindow on’ option and select ‘Mouse Click’ from drop down list.

Step 3: Save the map and open it in a browser.