I would suggest everyone to read this book:
Dissecting a C# Application: Inside SharpDevelop
A pdf version is available for download.
http://www.apress.com/free/
Things that you will learn includes
Chapter 1: Features at a Glance 7
Chapter 2: Designing the Architecture 23
Chapter 3: Implementing the Core 51
Chapter 4: Building the Application with Add-ins 81
Chapter 5: Providing Functionality with Workspace Services 107
Chapter 6: The User Interface 135
Chapter 7: Internationalization 169
Chapter 8: Document Management 189
Chapter 9: Syntax Highlighting 219
Chapter 10: Search and Replace 235
Chapter 11: Writing the Editor Control 263
Chapter 12: Writing the Parser 291
Chapter 13: Code Completion and Method Insight 329
Chapter 14: Navigating Code with the Class Scout and the Assembly Scout 369
Chapter 15: The Designer Infrastructure 413
Chapter 16: mplementing a Windows Forms Designer 437
Chapter 17: Code Generation 465