I have this simple example
http://comunivda.it/champorcher/test.html?html5=only
The red line (hotspot with zorder=10 t) is under the yellow hotspot (zorder=90): when you click on the yellow image a tooltip appear.
This is an HTML5 example;
The code of two hotpsot is very basic
Code
<hotspot name="sentiero_4" url="percorsi/9f.png"
capture="false" handcursor="false" zorder="10"
ath="222.418334" atv="9.174375" distorted="true" rx="0" ry="0" rz="4.184829" width="714" height="351" scale="0.512904"
/>
<hotspot name="segnavia3" url="images/AV2.png" ath="215.648533" atv="4.739349" style='fumetto' tooltip="Alta Via 2 - TdG tappa 3"/>
</scene>
<style name="fumetto"
zorder="90"
...
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If the page is viewed into a mobile device, the zorder is not correct and the red line hotspot is over the yellow image
I attach a screenshot with a Firefox Browser and IPhone simulator
The strange behavior is the mobile browser, not the html5 krpano mode
May be a bug?