After switching from Qt4.8 to Qt5.1.1 I found a change how a selectable QLabel reacts to double-clicks.

I have set the TextInteraction Flag:
label->setTextInteractionFlags(Qt::TextBrowserInteraction);

With Qt4 when double-clicking this Label the clicked word is selected (three clicks select all of the text).

With Qt5 there is no selection done when clicking the label. Only way to select text is by selecting it with hold down mouse button.

Is there a way to get the old style back? This would make the handling for the users much easier.