[Development] QWidget mouse events - different order

[Andreas Aardal Hanssen]

On 18 Dec 2013, at 22:07, Rayner Pupo Gómez <rpgomez at uci.cu> wrote:

>> I've discovered that with Qt5 I get a different order of mouse events on
>> a QWidget than with Qt4 (openSuse 13.1 Linux, X11):
>> double clicking a widget results in Qt4 in:
>> mousePressEvent 
>> mouseReleaseEvent 
>> mouseDoubleClickEvent 
>> mousePressEvent 
>> mouseReleaseEvent
>> but in Qt5 in:
>> mousePressEvent 
>> mouseReleaseEvent 
>> mousePressEvent 
>> mouseDoubleClickEvent 
>> mouseReleaseEvent 
>> I tested with Qt4.8.5 and Qt5.2.
>> Is this behavioral change intended, undefined, a bug ?
>> (it results in my app not behaving as before ...)
>> -- 
> 
> I think it's a mistake to rely on the order of this kind of events, there are 
> fired asynchronously, your logic cant depend on this

Wrong! The order is very essential and can and must be relied on.

The behaviour in Qt 5 is questionable. I believe the double-click must come first to be able to distinguish from two presses.

I also wonder if it’s accurate / true that Qt 4 sends the second press after the double-click. AFAIR:

Press
Release
DoubleClick
Release

Is the right events for double-clicking.

Andreas