I set UploadTYpePriority = "Html5,Flash,Siverlight". This works nicely everywhere except Safari for Windows - users see an alert box saying 'Your browser multiple file selection feature has bugs. Please select one file at a time".

If I change the priority to  "Flash,Html5,Siverlight" it works fine - but then flash is used instead of html5 in browsers that support html5.

Not a critical problem, but it would be nice if the uploader could switch to flash instead of showing the error message.