Multi-touch not working on Qt-5.x but works on Qt-4.8
I have an external screen (eGalax, vendor : 0xeef, product : 0x722e) and although my Ubuntu 14.04 recognizes multitouches from it (with program mtview for example, although not more than 2 touches), I can't get two fingers recognition on qt-5.3.1 or qt-5.4 :
I compiled and ran fingerpaint.pro (found on qt distributions) and it gets only one finger at a time.
However, if I run it with qt-4.8 (after includes modifications to get it to compile), I have two fingers recognition.
By the way, the MultiPointTouchArea in Qml programs (with the example found on qt doc) on qt-5.x don't work either (only one finger recognition), whereas it does what we want on an Android tablet.
When I install event filters on the fingerpaint program, I realized that qt-4.8 suitably distinguishes mouse clicks (Qt::MouseButtonPress) from finger taps (Qt::TouchBegin), whereas fingerpaint on qt-5.x only gives me Qt::MouseButtonPress, which should explain the problem.
Is that a bug (should I file it?), or is there any way to make qt-5 aware of finger events?
Thank you very much for any help on that matter.