Add centeredLabel support

src/QmlControls/QGCComboBox.qml

@@ -9,6 +9,7 @@ Button {
     id: combo
 
     property real   pointSize:      ScreenTools.defaultFontPointSize    ///< Point size for button text
+    property bool   centeredLabel:  false
     property alias  model:          popupItems.model
     property alias  textRole:       popup.textRole
     property alias  currentIndex:   popup.__selectedIndex
@@ -62,8 +63,10 @@ Button {
             QGCLabel {
                 id:                         text
                 anchors.verticalCenter:     parent.verticalCenter
+                anchors.horizontalCenter:   centeredLabel ? parent.horizontalCenter : undefined
                 text:                       control.currentText
                 color:                      control._qgcPal.buttonText
+                font.pointSize:             pointSize
             }
         }
     }