radegast from svn , start fail with mono-2.8.x

• Environment:

  Mono / Linux64

after installing mono-2.8x radegast crash on start

Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object
at System.Windows.Forms.Document.LineTagToCharIndex (System.Windows.Forms.Line line, Int32 pos) [0x00000] in <filename unknown>:0
at System.Windows.Forms.RichTextBox.set_SelectionColor (Color value) [0x00000] in <filename unknown>:0
at (wrapper remoting-invoke-with-check) System.Windows.Forms.RichTextBox:set_SelectionColor (System.Drawing.Color)
at Radegast.RichTextBoxPrinter.set_ForeColor (Color value) [0x00000] in <filename unknown>:0
at Radegast.ChatTextManager.ProcessBufferItem (Radegast.ChatBufferItem item, Boolean addToBuffer) [0x00000] in <filename unknown>:0
at Radegast.ChatTextManager.ReprintAllText () [0x00000] in <filename unknown>:0
at Radegast.ChatConsole.UpdateFontSize () [0x00000] in <filename unknown>:0
at Radegast.ChatConsole..ctor (Radegast.RadegastInstance instance) [0x00000] in <filename unknown>:0
at (wrapper remoting-invoke-with-check) Radegast.ChatConsole:.ctor (Radegast.RadegastInstance)
at Radegast.TabsConsole.InitializeChatTab () [0x00000] in <filename unknown>:0
at Radegast.TabsConsole..ctor (Radegast.RadegastInstance instance) [0x00000] in <filename unknown>:0
at (wrapper remoting-invoke-with-check) Radegast.TabsConsole:.ctor (Radegast.RadegastInstance)
at Radegast.frmMain.InitializeTabsConsole () [0x00000] in <filename unknown>:0
at Radegast.frmMain.InitializeControls () [0x00000] in <filename unknown>:0
at (wrapper remoting-invoke-with-check) Radegast.frmMain:InitializeControls ()
at Radegast.RadegastInstance..ctor (OpenMetaverse.GridClient client0) [0x00000] in <filename unknown>:0
at Radegast.RadegastInstance.get_GlobalInstance () [0x00000] in <filename unknown>:0
at Radegast.MainProgram.Main (System.String[] args) [0x00000] in <filename unknown>:0