Code Compare is a diff tool that compares text, source code, XML files and directories, then highlights differences and merges content via its visual interface. Code Compare can make version comparing and code reviews a much easier process.

Code Compare includes the following features:

• File compare compare two files at a time, with the ability to merge differences between compared files.
• Folder compare comparison of local/network directories, providing a visual interface for analyzing differences between two paths.
• Line compare allows for a single line comparison and replacement.
• Advanced Editing Options for easy file merging, including multi line copy, delete.
• Summary Bar gives a quick overview of differences between files or directories.

This was a side project some time in the early 2000s (around .net 2.0 era). However recently resurected when .net core 3.0 promised & delivered a WinForms implementation.