Markdown preview steals focus

[ymmt2005]

• code-server version: 1.868-vsc1.33.1
• OS Version: Ubuntu 18.04

Description

Preview window of markdown steals focus while editing the corresponding markdown file.

Steps to Reproduce

1. Open preview window to the side.
2. Edit the markdown file.
   For example, try to add following texts:

   ### abc

   As the preview window steals focus, you will not be able to write abc.