Prevent Show a UserControl in ToolBox

Problem:
- I don't want User Controls showing up in the toolbox
- How to put out a UserControl from Visual Studio ToolBox
- My user controls appear in tool box
- User control must not show in toolbox
- Prevent a base class from VS2012 toolbox

Solution:
Just Add these lines to top of your class.
PS: The first line is enough

[System.ComponentModel.DesignTimeVisible(false)]
[System.ComponentModel.ToolboxItem(false)]