Range Slider qt.labs.controls not usable (Material, Universal)

The RangeSlider from qt.labs.controls example app isn't usable from Material and Universal on my BlackBerry PRIV.
Slider is working, but Range Slider have to try 4 or 5 times before a handle could be dragged.
In Default style it works - but there the control is larger, so perhaps the area where my fingertip was noticed by the control, too