I created a TextBoxControl which is inherited from Infragistics.Win.UltraWinEditors.UltraTextEditor, an Infragistics control. As showed below.

public class TextBoxControl : Infragistics.Win.UltraWinEditors.UltraTextEditor
{
  //My Stuff
}

At some level Infragistics.Win.UltraWinEditors.UltraTextEditor class also inherited from WinForm's "Control" class. My problem is, this control is not appearing in the ToolBox. I done two steps 1. Choose from browse option and select the dll where the class present 2. Drag and drop the dll directly to the ToolBox

In-fact both are same, TextBoxControl control is not appearing in the ToolBox, what i missing here.

Edit : TextBoxControl class have empty constructor, nothing special in this class.