Thanks for the pipes, I'll try to stick with your 2nd example.
<style name="style3" style="style1|style2" />
<hotspot name="myhotspot" style="style3" />
I imagine my example was never meant to be working in 1.19 either and it was just luck.
But it seemed so straightforward and so easy in krpano's documentation : "When the xml element will be first created, all attributes defined at the <style> element will be copied to the element itself." I guess this sentence is wrong when the xml element is a style.
Thanks!
Florian