Fix button z-order

src/MissionEditor/MissionEditor.qml

@@ -551,18 +551,17 @@ QGCView {
                     anchors.left:       parent.left
                     anchors.top:        parent.top
                     spacing:            ScreenTools.defaultFontPixelHeight
+                    z:                  QGroundControl.zOrderWidgets
 
                     RoundButton {
                         id:             addMissionItemsButton
                         buttonImage:    "/qmlimages/MapAddMission.svg"
-                        z:              QGroundControl.zOrderWidgets
                         lightBorders:   _lightWidgetBorders
                     }
 
                     RoundButton {
                         id:             addShapeButton
                         buttonImage:    "/qmlimages/MapDrawShape.svg"
-                        z:              QGroundControl.zOrderWidgets
                         visible:        QGroundControl.experimentalSurvey
                         lightBorders:   _lightWidgetBorders
 
@@ -584,7 +583,6 @@ QGCView {
                         buttonImage:        syncNeeded ? "/qmlimages/MapSyncChanged.svg" : "/qmlimages/MapSync.svg"
                         viewportMargins:    ScreenTools.defaultFontPixelWidth / 2
                         exclusiveGroup:     _dropButtonsExclusiveGroup
-                        z:                  QGroundControl.zOrderWidgets
                         dropDownComponent:  syncDropDownComponent
                         enabled:            !controller.syncInProgress
                         rotateImage:        controller.syncInProgress
@@ -597,7 +595,6 @@ QGCView {
                         buttonImage:        "/qmlimages/MapCenter.svg"
                         viewportMargins:    ScreenTools.defaultFontPixelWidth / 2
                         exclusiveGroup:     _dropButtonsExclusiveGroup
-                        z:                  QGroundControl.zOrderWidgets
                         lightBorders:       _lightWidgetBorders
 
                         dropDownComponent: Component {
@@ -643,7 +640,6 @@ QGCView {
                         buttonImage:        "/qmlimages/MapType.svg"
                         viewportMargins:    ScreenTools.defaultFontPixelWidth / 2
                         exclusiveGroup:     _dropButtonsExclusiveGroup
-                        z:                  QGroundControl.zOrderWidgets
                         lightBorders:       _lightWidgetBorders
 
                         dropDownComponent: Component {
@@ -676,7 +672,6 @@ QGCView {
                         id:             mapZoomPlus
                         visible:        !ScreenTools.isTinyScreen && !ScreenTools.isShortScreen
                         buttonImage:    "/qmlimages/ZoomPlus.svg"
-                        z:              QGroundControl.zOrderWidgets
                         lightBorders:   _lightWidgetBorders
 
                         onClicked: {
@@ -691,7 +686,6 @@ QGCView {
                         id:             mapZoomMinus
                         visible:        !ScreenTools.isTinyScreen && !ScreenTools.isShortScreen
                         buttonImage:    "/qmlimages/ZoomMinus.svg"
-                        z:              QGroundControl.zOrderWidgets
                         lightBorders:   _lightWidgetBorders
                         onClicked: {
                             if(editorMap)