QDoubleSpinBox + MousePressEvent

Question

I am trying to implement my own version of the QDoubleSpinBox to have it act like in Maya with int/FloatFields so you can Ctrl+click+drag to change the value.

I have this system working on a QLabel by setting the text from my value but then when I try to do it on a QDoubleSpinBox I have a problem with the mousePressEvent. It only works on the arrowButtons, not it the field itself...

here is my initial code :

class MayaLikeDoubleField(QtGui.QDoubleSpinBox):
    def __init__(self, parent):
        super(MayaLikeDoubleField, self).__init__()

        self.offset = 0

    def mousePressEvent(self, event):
        self.offset = event.x()

    def mouseMoveEvent(self, event):
        modifiers = QtGui.QApplication.keyboardModifiers()
        if modifiers == QtCore.Qt.ControlModifier:
            QtGui.QWidget.mouseMoveEvent(self, event)
            relPos = event.x()-self.offset
            print relPos*0.01
            # instead of printing I would set the value.

In this case, it doesn' work. So I have tried this :

class Widget(QtGui.QWidget):
    def __init__(self):
        super(Widget, self).__init__()
        self.layout = QtGui.QHBoxLayout(self)

        self.sbox = QtGui.QDoubleSpinBox()
        self.layout.addWidget(self.line)
        self.sbox.installEventFilter(self)

    def mousePressEvent(self, event):
        print "Main Widget Mouse Press"
        super(Widget, self).mousePressEvent(event)

    def eventFilter(self, obj, event):
        modifiers = QtGui.QApplication.keyboardModifiers()
        if modifiers == QtCore.Qt.ControlModifier:
            if self.layout.indexOf(obj) != -1:
                if event.type() == event.MouseButtonPress:
                    print "Widget click"
                if event.type() == event.MouseMove:
                    print "Widget Move"
         return super(Widget, self).eventFilter(obj, event)

And surprise ! it doesn't work ... but if i replace the QDoubleSpinBox by a QLineEdit it does work ... why ? for me it works the same way as by default the mousePressButton doesn't work on it...

Is there anything special that I am missing ?

Thanks !