Description: If URL is added to a polygon hotspot it will not be saved in the project file. I created a new polygon spot style, Changed the the action to 'Basic > Open a website, then created a polygon hotspot choose the 'open a website' style, filled in a website at the action parameters, pressed save project. Closed the program reopened the project file and the website parameter is gone.
This works in version 1.8.
It needed to open websites in new tabs as we did in the past versions.