How to use:

On the Project View tool window, locate the gear icon, then click on it and select Enable Preview Tab option. After that, click on a file in the Project View and it will allow you to preview its contents without creating a new tab that you then need to close.

Pro tip: You can also locate the Enable Preview Tab option using ⇧⇧ (macOS) / Shift+Shift (Windows/Linux), and turn it on.