Disable preview mode in VS Code

What is the difference between the left and the right file? The right one is opened in preview mode.

Opening another file won't result in a new tab. Instead, the preview tab is changed to the new file - meaning the file currently previewed is closed.

The preview mode is used e.g. when you click on a file in the explorer or open a file through the Quick Open feature (Ctrl + p).

The following settings will disable the preview mode:

"workbench.editor.enablePreview": false,
"workbench.editor.enablePreviewFromQuickOpen": false

For more information on the preview mode, check out the official documentation.