private static TpTool PrimitiveTool(Primitive primitive)
{
if (primitive is FreeLine)
return TpTool.FreeLine;
if (primitive is Line)
return TpTool.Line;
if (primitive is DecoratedTextBox)
return TpTool.TextBox;
if (primitive is Box)
return TpTool.Box;
return TpTool.Select;
}