Hi Huzaifa Gain,
I am not sure whether these information can help you. If you need any detail requirement, please feel free to tell me.
Developing Windows Forms Controls at Design Timehttp://msdn.microsoft.com/en-us/library/w29y3h59.aspx
Design time FAQhttp://www.syncfusion.com/FAQ/windowsforms/faq_c83c.aspx
Writing Custom Designers for .NET Componentshttp://msdn.microsoft.com/en-us/library/ms973820.aspx
Sincerely,Kira Qian