Adding a Windows User Control to your Toolbox
Click on Tools in the menu bar,
select Add/Remove Toolbar Items
Click on the .NET Framework Components tab
click the Browse button
Find the control's .dll file in its bin folder (browse to it) and select it.
The control will appear selected in the .NET Framework Components tab
Once the dialog box is closed, the control will appear at the bottom of the toolbox.
Contributed by Andrea Holloway