How to put a ComboBox into a GroupBox ?

[D_Blade]

Hi guys,

I got some issues with putting a ComboBox into a GroupBox. Currently I am using QT 5.5

I start with the following setup:

import QtQuick 2.0
import QtQuick.Layouts 1.1
import QtQuick.Controls 1.4
import QtQuick.Controls.Styles 1.4

GridLayout{
    columns: 1
    Layout.fillWidth: true
    Layout.fillHeight: true

    ComboBox{
        model: [ "No items" ]
        Layout.fillWidth: true
        style: ComboBoxStyle{
            label: Text {
                verticalAlignment: Text.AlignVCenter
                horizontalAlignment: Text.AlignHCenter
                color: "red"
                text: control.currentText
            }
        }
    }
}

Looks good, so far. Now I want a frame with a title around that and GroupBox is the perfect element for that. So I just put a GroupBox {<code_above>} around the whole thing right ? But once I do that, my ComboBox starts to look distorted. (ComboBox not scaling with the width properly). It gets better, if I remove my ComboBoxStyle and/or the GridLayout, but it still does not scale the whole width. Even if I apply

Layout.fillWidth: true
Layout.fillHeight: true

for the GroupBox. I also tried to view the QML file with qmlscene, but no difference.

So how can I get that ComboBox to use the full width just like it does without the GroupBox?