slider: if a ladder appears, signal the label that the drag has finished

app/widget/slider/sliderbase.cpp

@@ -260,6 +260,8 @@ void SliderBase::LabelDragged()
 
     connect(drag_ladder_, &SliderLadder::DraggedByValue, this, &SliderBase::LadderDragged);
     connect(drag_ladder_, &SliderLadder::Released, this, &SliderBase::LadderReleased);
+
+    label_->CancelDrag();
     break;
   }
 }

app/widget/slider/sliderlabel.h

@@ -33,6 +33,11 @@ class SliderLabel : public QLabel
 public:
   SliderLabel(QWidget* parent);
 
+  void CancelDrag()
+  {
+    dragging_ = false;
+  }
+
 protected:
   virtual void mousePressEvent(QMouseEvent *ev) override;