Hello, krpano player is not able to link the zoom value with flat panoramas. Why? Because flat panoramas are not flat but used a sphere with less than 1° fov. So with zoom activated the icon use all the space. It's why Panotour deactivate the zoom attribute on flat panoramas.
A possible solution is to define a size for your hotspot and remove the Panotour limitation. How to do? - Edit the YOURTOURNAME.xml file and add width="0.2" and height="0.2" attributes to the selected spot into the specified scene. (these values must be changed for your own scene) - Edit the YOURTOURNAME_skin.xml file and remove the if(scene[get(xml.scene)].planar,if(zoom,set(zoom, false););); string from the onloaded attribute of the hotspot style linked to the hotspot.