Uninstall Postman and Vysor

If Vysor and Postman are chrome extensions, you should uninstall from chrome menu. Tools->Extensions, find the extension on the list and click uninstall.

In my case I also had the Vysor icon on the main menu, and after uninstalled from chrome extensions it disappears automatically.

sudo apt-get purge postman

If not work:

sudo snap remove postman