Fix binding loops

src/QmlControls/MissionItemIndexLabel.qml

 import QtQuick          2.3
 import QtQuick.Controls 1.2
-import QtQuick.Controls.Styles  1.4
 
 import QGroundControl.ScreenTools 1.0
 import QGroundControl.Palette     1.0
@@ -69,12 +68,9 @@ Canvas {
 
     Rectangle {
         id:                     labelControl
-        anchors.leftMargin: -_labelMargin
-        anchors.topMargin:  -_labelMargin
-        anchors.left:       indicator.left
-        anchors.top:        indicator.top
-        height:             _labelRadius * 2
-        width:              labelControlLabel.contentWidth + (_labelMargin * 3) + indicator.width
+        anchors.leftMargin:     -((_labelMargin * 2) + indicator.width)
+        anchors.rightMargin:    -(_labelMargin * 2)
+        anchors.fill:           labelControlLabel
         color:                  "white"
         opacity:                0.5
         radius:                 _labelRadius
@@ -83,17 +79,16 @@ Canvas {
 
     QGCLabel {
         id:                     labelControlLabel
-        anchors.leftMargin:     indicator.width + _labelMargin
-        anchors.left:           labelControl.left
-        anchors.rightMargin:    _labelMargin
-        anchors.right:          labelControl.right
-        anchors.top:            labelControl.top
-        anchors.bottom:         labelControl.bottom
-        verticalAlignment:      Text.AlignVCenter
+        anchors.topMargin:      -_labelMargin
+        anchors.bottomMargin:   -_labelMargin
+        anchors.leftMargin:     _labelMargin
+        anchors.left:           indicator.right
+        anchors.top:            indicator.top
+        anchors.bottom:         indicator.bottom
         color:                  "white"
-        font.pointSize:         ScreenTools.defaultFontPointSize
-        fontSizeMode:           Text.HorizontalFit
         text:                   _label
+        verticalAlignment:      Text.AlignVCenter
+        visible:                labelControl.visible
     }
 
     Rectangle {