GetTrayLocation now return with GetDeviceCoordinates. Fix in the case of multi-monitor.

Add extension point CustomPopupPosition to show Balloon on custom position.
AppBarInfo.WorkArea now return appbar workarea. Before it returns screen workarea.

Hardcodet.NotifyIcon.Wpf/Source/NotifyIconWpf/TaskbarIcon.cs

@@ -145,6 +145,14 @@ namespace Hardcodet.Wpf.TaskbarNotification
         #endregion
 
         #region Custom Balloons
+        public delegate Point GetCustomPopupPosition();
+
+        public GetCustomPopupPosition CustomPopupPosition;
+
+        public Point GetPopupTrayPosition()
+        {
+          return TrayInfo.GetTrayLocation();
+        }                                              
 
         /// <summary>
         /// Shows a custom control as a tooltip in the tray location.
@@ -217,8 +225,8 @@ namespace Hardcodet.Wpf.TaskbarNotification
             popup.Placement = PlacementMode.AbsolutePoint;
             popup.StaysOpen = true;
 
-            Point position = TrayInfo.GetTrayLocation();
-            position = GetDeviceCoordinates(position);
+            
+            Point position = this.CustomPopupPosition != null ? this.CustomPopupPosition() : this.GetPopupTrayPosition();
             popup.HorizontalOffset = position.X - 1;
             popup.VerticalOffset = position.Y - 1;
 
@@ -394,7 +402,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
                 WinApi.GetCursorPos(ref cursorPosition);
             }
 
-            cursorPosition = GetDeviceCoordinates(cursorPosition);
+            cursorPosition = TrayInfo.GetDeviceCoordinates(cursorPosition);
 
             bool isLeftClickCommandInvoked = false;
 
@@ -954,16 +962,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
 
         #endregion
 
-        /// <summary>
-        /// Recalculates OS coordinates in order to support WPFs coordinate
-        /// system if OS scaling (DPIs) is not 100%.
-        /// </summary>
-        /// <param name="point"></param>
-        /// <returns></returns>
-        private Point GetDeviceCoordinates(Point point)
-        {
-          return new Point() { X = (int)(point.X / SystemInfo.DpiXFactor), Y = (int)(point.Y / SystemInfo.DpiYFactor) };
-        }
+
 
         #region Dispose / Exit