slider: fixed crash when clicking another mouse button while dragging

app/widget/slider/sliderlabel.cpp

@@ -51,10 +51,12 @@ SliderLabel::SliderLabel(QWidget *parent) :
 
 void SliderLabel::mousePressEvent(QMouseEvent *e)
 {
-  if (e->modifiers() & Qt::AltModifier) {
-    emit RequestReset();
-  } else {
-    emit LabelPressed();
+  if (e->button() == Qt::LeftButton) {
+    if (e->modifiers() & Qt::AltModifier) {
+      emit RequestReset();
+    } else {
+      emit LabelPressed();
+    }
   }
 }
 

app/widget/slider/sliderladder.cpp

@@ -103,9 +103,7 @@ void SliderLadder::mouseReleaseEvent(QMouseEvent *event)
 {
   Q_UNUSED(event)
 
-  drag_timer_.stop();
-
-  emit Released();
+  this->close();
 }
 
 void SliderLadder::showEvent(QShowEvent *event)
@@ -115,6 +113,15 @@ void SliderLadder::showEvent(QShowEvent *event)
   drag_timer_.start();
 }
 
+void SliderLadder::closeEvent(QCloseEvent *event)
+{
+  Q_UNUSED(event)
+
+  drag_timer_.stop();
+
+  emit Released();
+}
+
 void SliderLadder::TimerUpdate()
 {
   int32_t x_mvmt, y_mvmt;

app/widget/slider/sliderladder.h

@@ -75,6 +75,8 @@ protected:
 
   virtual void showEvent(QShowEvent *event) override;
 
+  virtual void closeEvent(QCloseEvent* event) override;
+
 signals:
   void DraggedByValue(int value, double multiplier);