Touch events are not detected in Qt/QML

Some versions of Qt detect Touch Events (QEvent::TouchBegin, etc.), some do not. In Qml, this translates into multi-touch not being recognized for the latter.

I tried two programs: fingerpaint.pro and window.pro, which can be found in qt examples.

They actually do what we want with version of Qt installed on Ubuntu 14.04 (QMake version 3.0, Using Qt version 5.2.1 in /usr/lib/x86_64-linux-gnu), but they don't if I download qt versions (5.2.1, 5.3.1, 5.4.0) with the online installer: no QEvent::TouchBegin or other similar event is detected (mouse press instead), and thus only one finger at a time is recognized in MultiPointTouchArea.

There is a trick to make the programs compiled with the 5.2.1 (downloaded) version work: remove libQt5Core.so so that it uses the one found in /usr/lib/x86_64-linux-gnu/. The same workaround does not work for versions 5.3.1 and 5.4 because the programs do not compile anymore.

Thank you.