How to prevent Docky from displaying an app twice?

Question

linux

Launched chromium from console. A chromium icon has appeared in the Docky dock. Pinned her up. Then I made this .desktop shortcut myself:

[Desktop Entry]
Type=Application
Name=Вконтакте
Exec=chromium --window-size=400,600 --window-position=450,100 --app=https://m.vk.com
Icon=web-vk

And added this shortcut to the Docky panel. Now when I launch my shortcut, the Chromium shortcut also opens. That is, it turns out like this:

How can I make it so that when I launch my shortcut on the panel, only it opens, but not chromium?