Note: Advice in this article will only work for DotNetBrowser 1.
See the corresponding article for DotNetBrowser 2 here.

When your application is running, you can notice several DotNetBrowser.Chromium.exe processes in the task manager. These processes are always the child processes of your application’s process.

DotNetBrowser brings its own Chromium-based engine, and this engine uses these processes to do all the Chromium-related work. The more browser instances you create, the more processes will be started. After the browser instance is disposed properly, the processes related to that instance will terminate automatically.

If the browser instance or the browser view were not disposed properly, they will remain in memory and prevent your application from closing. The processes related to these instances will also remain running.

The following article explains how to dispose a Browser instance properly:

Disposing Browser