Hi klaus,
is there possible you 'll implement one day a new function/attribute for hotspot :
on_pov=appear
on_pov=disappear
on_pov=nothing (defaut)
so invisible hotspot may appear with fade in and disappear with fade out at time they pass on center screen (point of view of visitor) while pano pan.
or in contrary dissapear so doesn't disturb the view (example of image hotspot)
i think is do-able with conditionnals : if pano.pan is equal to hotspot pan then hotspot visible... with a range of 20° for fadein/out off the position...
to illustrate this, see this cool plugin for FPP by duncan :
http://www.redshift-blueshift.com/panofiles/zoetrope/Zoetrope.html
it will be cool if it come as buil-in function
see u