Run quicknanobrowser example:
1) Go to http://www.w3schools.com/tags/tryit.asp?filename=tryhtml_select
2) Click on select box
3) Try to click on option, none of the options are clickable
4) key selection works though.

Same works in demobrowser, so possibly a qt quick web engine issue.

Doesn't work on any of the relatively latest git heads of 5.6, 5.7, 5.8.
Did work with official 5.6.0 and 5.6.1 binaries.