It is possible (andy very easy to reproduce) to have more than one item open with singleItemOpen: true
Only one Item is open at a time
More then one item is open
Just create new List with a high duration (i used 1000) and click fast on a few items.
More than one item opens.
I tried this in a few different Browsers (Chrome 52, FF 48, IE11...), it happens in all of them
It seems there is no workaround so unfortunately this makes the project unusable for me :/
🐛 Fix #63: Short circuit out if other items are opening