fix conflict

Author: ButchersBoy

MainDemo.Wpf/Buttons.xaml

@@ -80,7 +80,9 @@
                 <materialDesign:PopupBox Style="{StaticResource MaterialDesignMultiFloatingActionPopupBox}"
                                          PlacementMode="BottomAndAlignCentres"
                                          ToolTipService.Placement="Right"
-                                         ToolTip="PopupBox, Style MaterialDesignMultiFloatingActionPopupBox">
+                                         ToolTip="PopupBox, Style MaterialDesignMultiFloatingActionPopupBox"
+                                         OnPopupOpened="PopupBox_OnPopupOpened"
+                                         OnPopupClosed="PopupBox_OnPopupClosed">
                     <StackPanel>
                         <Button ToolTip="One">1</Button>
                         <Button ToolTip="Two">2</Button>

MainDemo.Wpf/Buttons.xaml.cs

@@ -39,5 +39,15 @@ private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
 	    {
             Console.WriteLine("Just checking we haven't suppressed the button.");
 		}
+
+        private void PopupBox_OnPopupOpened(object sender, RoutedEventArgs e)
+        {
+            Console.WriteLine("Just making sure the popup has opened.");
+        }
+
+        private void PopupBox_OnPopupClosed(object sender, RoutedEventArgs e)
+        {
+            Console.WriteLine("Just making sure the popup has closed.");
+        }
     }
 }

MaterialDesignThemes.Wpf/PopupBox.cs

@@ -242,6 +242,25 @@ private static void IsPopupOpenPropertyChangedCallback(DependencyObject dependen
                 else
                     Mouse.Capture(null);
             }
+
+            if (newValue)
+            {
+                var popupOpenedEventArgs = new RoutedEventArgs()
+                {
+                    RoutedEvent = OnPopupOpenedEvent,
+                    Source = popupBox
+                };
+                popupBox.RaiseEvent(popupOpenedEventArgs);
+            }
+            else
+            {
+                var popupClosedEventArgs = new RoutedEventArgs()
+                {
+                    RoutedEvent = OnPopupClosedEvent,
+                    Source = popupBox
+                };
+                popupBox.RaiseEvent(popupClosedEventArgs);
+            }
 
             popupBox.AnimateChildrenIn(!newValue);                 
             popupBox._popup?.RefreshPosition();
@@ -258,6 +277,45 @@ public bool IsPopupOpen
             set { SetValue(IsPopupOpenProperty, value); }
         }
 
+        /// <summary>
+        /// Event corresponds to the popup opening
+        /// </summary>
+        public static readonly RoutedEvent OnPopupOpenedEvent = 
+            EventManager.RegisterRoutedEvent(
+                "OnPopupOpened", 
+                RoutingStrategy.Bubble, 
+                typeof(RoutedEventHandler), 
+                typeof(PopupBox));
+
+        /// <summary>
+        /// Event corresponds to the popup closing
+        /// </summary>
+        public static readonly RoutedEvent OnPopupClosedEvent = 
+            EventManager.RegisterRoutedEvent(
+                "OnPopupClosed", 
+                RoutingStrategy.Bubble, 
+                typeof(RoutedEventHandler), 
+                typeof(PopupBox));
+
+        /// <summary>
+        /// Add / Remove OnPopupOpenedEvent handler 
+        /// </summary>
+        public event RoutedEventHandler OnPopupOpened
+        {
+            add { AddHandler(OnPopupOpenedEvent, value); }
+            remove { RemoveHandler(OnPopupOpenedEvent, value); }
+        }
+
+        /// <summary>
+        /// Add / Remove OnPopupClosedEvent handler 
+        /// </summary>
+        public event RoutedEventHandler OnPopupClosed
+        {
+            add { AddHandler(OnPopupClosedEvent, value); }
+            remove { RemoveHandler(OnPopupClosedEvent, value); }
+        }
+
+
         public static readonly DependencyProperty StaysOpenProperty = DependencyProperty.Register(
             nameof(StaysOpen), typeof (bool), typeof (PopupBox), new PropertyMetadata(default(bool)));