A clone of Notepad written for a compiled/run against Mono 2.10.
You CAN target .NET 4 with this but please note that if you do, your compatibility with the Mono runtime is decreased. If you are using Visual Studio 2010/2012(?), please use the following instructions from http://erictummers.wordpress.com/2012/01/25/target-mono-from-visual-studio/ to get target Mono in Visual Studio.
NOTE: These steps are assuming you already have the latest version of the Mono Runtime installed. (1). Download the following: http://www.box.com/s/qligmtyer2log12k9027 (2). Extract the archive anywhere. (3). Navigate to (replace X with your local drive letter) X:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\Profile (4). Copy the "mono" folder into this directory. You will need administration access for it. (5). Run the proper .reg key for your system (32 or 64 bit). (6). ??? (7). Profit.