I have a file, xyz.cpp. I want to open two instances of this file in Visual studio (BTW, I am using Visual Studio 2005). Why would I want to do so? I want
Go to menu → Windows → New Window:
Here's how to do it...
If New Window is not listed in the *Window menu note that the command does exist, even as of Visual Studio 2017. Add it to the Window menu using menu Tools → Customize → Commands. At that point decide where to put the New Window command and select Add Command.
UPDATED on "30 July 2018"
In Visual Studio Code version 1.25.1 and later
Way 1
You can simple left click on your file in the side-panel (explorer) and press Ctrl + Enter.
Way 2
Simply right click on your file in the Visual Studio Code side-panel (explorer) and select the first option open to the side.
For newer versions (such as Visual Studio 2017)