GIMP icon in GNOME Classic's window list changes after opening an image

Question

I am using Ubuntu 18.04 with GNOME Classic. With GNOME Classic I use window list, this shows me all my currently open apps:

When I open a file in GIMP, the icon in the window list changes and appear an icon related with the image appears.

GIMP icon in window list before opening an image:

GIMP icon in window list after opening an image:

Is there a way to disable this behavior?

I want to keep the GIMP icon always.

For example, for Firefox, OpenOffice, Chrome the icons never change. It always shot the program icon, not an icon representing the page or document open.

Answer 1

I fixed this by finding .desktop file for Gimp find / | grep gimp.desktop and adding new line with StartupWMClass=Gimp-2.10. But this solution is version-specific and needs to be updated with each new version release.

You can find your Gimp's WMClass with xprop WM_CLASS command and clickling into Gimp window.