I'm currently running Ubuntu GNOME 17.04 on my laptop. I didn't like the default theme (Adwaita), so I replaced it with the Arc Icon, GTK+ and Shell theme.
The theme works fine, but I noticed that the icons that usually come next to the name of the currently running application in the top bar don't appear any more (e.g. While running Firefox, only the name appears. The Firefox logo doesn't).
Is there any way that I can fix this?