XISelectEvents override any earlier set event mask for the same device
ids. This may cause touch devices to stop reporting touch events if they
export scroll buttons or axis.
The patch checks for each scrolling device if they are also a touch
devices and includes the necessary bitmask if they are, and skips
any devices also recognized as tablet devices as they already capture
all relevant events.
In addition tablet event handling will no longer block handling of wheel
button events for scroll devices with the same device id.
Task-number: QTBUG-38935
Change-Id: Ifd4657beb0a0cebffe89d3470ef2bd605eb3552e
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
a8877f529d