Crash when messaging players in game lobby

[GrantBartlett]

When in an online game, right click a player and select "Private message", and it will instant crash.

01.01. 22:26:09.292    KABOOOOOOM!!! Info:
01.01. 22:26:09.292    Type: System.NullReferenceException
01.01. 22:26:09.292    Message: Object reference not set to an instance of an object.
01.01. 22:26:09.293    Source: clientdx
01.01. 22:26:09.294    TargetSite.Name: <Initialize>b__22_0
01.01. 22:26:09.294    Stacktrace:    at DTAClient.DXGUI.Multiplayer.CnCNet.GlobalContextMenu.<Initialize>b__22_0() in C:\Dev\xna-cncnet-client\DXMainClient\DXGUI\Multiplayer\CnCNet\GlobalContextMenu.cs:line 65
   at Rampastring.XNAUI.XNAControls.XNAContextMenu.OnLeftClick()
   at Rampastring.XNAUI.XNAControls.XNAControl.Update(GameTime gameTime)
   at Rampastring.XNAUI.XNAControls.XNAContextMenu.Update(GameTime gameTime)
   at Rampastring.XNAUI.WindowManager.Update(GameTime gameTime)
   at Microsoft.Xna.Framework.Game.SortingFilteringCollection`1.ForEachFilteredItem[TUserData](Action`2 action, TUserData userData)
   at Microsoft.Xna.Framework.Game.DoUpdate(GameTime gameTime)
   at Microsoft.Xna.Framework.Game.Tick()
   at MonoGame.Framework.WinFormsGameWindow.TickOnIdle(Object sender, EventArgs e)
   at System.Windows.Forms.Application.ThreadContext.System.Windows.Forms.UnsafeNativeMethods.IMsoComponent.FDoIdle(Int32 grfidlef)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at MonoGame.Framework.WinFormsGameWindow.RunLoop()
   at Microsoft.Xna.Framework.Game.Run(GameRunBehavior runBehavior)
   at DTAClient.Startup.Execute() in C:\Dev\xna-cncnet-client\DXMainClient\Startup.cs:line 157
   at DTAClient.PreStartup.Initialize(StartupParams parameters) in C:\Dev\xna-cncnet-client\DXMainClient\PreStartup.cs:line 213