SpinBox with in RowLayout

I add some simple spinbox in a row layout, but the behaviour seems buggy, the spinbox with (implicit width i assume) is broken:

RowLayout {
SpinBox

{ value: 55 }

SpinBox

{ decimals: 2 }

SpinBox

{ minimumValue: 10.2; maximumValue: 10.5; stepSize: 0.01; decimals: 3 }

SpinBox

{ minimumValue: 0; maximumValue: 100; value: 33; suffix: "%" }

SpinBox

{ value: 33; enabled: false }

SpinBox

{ prefix: "prefix"; suffix: "suffix"; value: 22 }

Item

{ Layout.fillWidth: true }

}

See topic :
http://qt-project.org/forums/viewthread/39681/#168322