Index: sources/gui/qml/components/RangeMarker.qml
===================================================================
diff -u -r3e91f569d10fe5b76298b85ee3a6875f80e33063 -r0022c3993c47e74c2d17c7f07f78fa1751a034f6
--- sources/gui/qml/components/RangeMarker.qml	(.../RangeMarker.qml)	(revision 3e91f569d10fe5b76298b85ee3a6875f80e33063)
+++ sources/gui/qml/components/RangeMarker.qml	(.../RangeMarker.qml)	(revision 0022c3993c47e74c2d17c7f07f78fa1751a034f6)
@@ -81,6 +81,23 @@
             rightMargin : valueOnTop ? -12 : 5
             topMargin   : valueOnTop ? 0 : -5
             horizontalCenter: valueOnTop ? _handle.horizontalCenter : undefined
+            horizontalCenterOffset: {
+                if (valueOnTop) {
+                    if (_root.parent !== undefined) {
+                        let xDelta = (_root.width-implicitWidth)/2
+                        // left boundary
+                        if (_root.x + xDelta < 0) {
+                            return -(_root.x + xDelta)
+                        }
+                        // right boundary
+                        let rightOverflow = _root.x + _root.width - xDelta
+                        if (rightOverflow > _root.parent.width) {
+                            return -(rightOverflow - _root.parent.width)
+                        }
+                    }
+                }
+                return 0
+            }
         }
         horizontalAlignment: valueOnTop ? Text.AlignHCenter : Text.AlignLeft
         color   : _root.color