Add MenuButton control.

src/editors/xrSdkControls/Controls/MenuButton.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Drawing;
+using System.Windows.Forms;
+
+namespace XRay.SdkControls
+{
+    public class MenuButton : Button
+    {
+        private ContextMenu menu = new ContextMenu();
+
+        protected override void OnClick(EventArgs e)
+        {
+            // for ContextMenuStrip
+            //var screenPoint = PointToScreen(new Point(Left, Bottom));
+            //var currentScreen = Screen.FromPoint(screenPoint);
+            //var flip = screenPoint.Y + menu.Size.Height > currentScreen.WorkingArea.Height;
+            //menu.Show(this, new Point(0, flip ? -menu.Height : Height));
+            menu.Show(this, new Point(0, Height));
+            base.OnClick(e);
+        }
+
+        protected override void OnPaint(PaintEventArgs e)
+        {
+            base.OnPaint(e);
+            int arrowX = ClientRectangle.Width-14;
+            int arrowY = ClientRectangle.Height/2-1;
+            var brush = Enabled ? SystemBrushes.ControlText : SystemBrushes.ButtonShadow;
+            var arrowPoints = new []
+            {
+                new Point(arrowX, arrowY),
+                new Point(arrowX+7, arrowY),
+                new Point(arrowX+3, arrowY+4)
+            };
+            e.Graphics.FillPolygon(brush, arrowPoints);
+        }
+
+        public ContextMenu Menu
+        {
+            get { return menu; }
+        }
+    }
+}

src/editors/xrSdkControls/xrSdkControls.csproj

@@ -49,6 +49,9 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Controls\MenuButton.cs">
+      <SubType>Component</SubType>
+    </Compile>
     <Compile Include="Controls\ColorPicker\ColorPicker.cs">
       <SubType>UserControl</SubType>
     </Compile>