Index: sources/gui/qml/components/ValueControl.qml
===================================================================
diff -u -r7dd8afa47f44f25221b167e3dc506df6dd287606 -r8b84749609138274fb1b899c7862239f12ea2f41
--- sources/gui/qml/components/ValueControl.qml	(.../ValueControl.qml)	(revision 7dd8afa47f44f25221b167e3dc506df6dd287606)
+++ sources/gui/qml/components/ValueControl.qml	(.../ValueControl.qml)	(revision 8b84749609138274fb1b899c7862239f12ea2f41)
@@ -82,7 +82,7 @@
         MouseArea { id: _sliderMouseArea
             property bool grabbed: false
 
-            anchors.fill: parent
+            anchors.fill        : parent
             pressAndHoldInterval: _root.holdInterval
 
             onClicked: {
@@ -104,15 +104,24 @@
 
             onPositionChanged: {
                 if (grabbed) {
+                    if ( _slider.opacity === 0 ) { _animator.start() }
+
                     _slider.pos = Math.max(0, Math.min(1, mouse.x / parent.width))
                     let raw =  _slider.from + _slider.pos * (_slider.to - _slider.from)
                     let stepped = Math.round((raw - _slider.from) / _root.step) * _root.step + _slider.from
                     _root.value = stepped
                 }
             }
+
+            onExited: {
+                if ( ! _sliderMouseArea.grabbed ) {
+                    _animator.stop()
+                    _slider.opacity = 0
+                }
+            }
         }
 
-        OpacityAnimator {
+        OpacityAnimator { id: _animator
             target  : _slider
             from    : 0
             to      : 1