Through javascript you would be able to open the infowindow when the page is loaded.

Maybe we can change it in the addon, but for now you can try it yourself.

Check the function click_sidebar(idx).
idx should be the number of the marker that you want to open. 0 opens the first one.

Hope it works!

Regards,

Corretje

Note: Sorry for the delay, due to vacation and work I wasn't able to work on the support requests.

Excellent. Thank you, that worked perfectly.