So, I installed nheko matrix client yesterday from our stable repo.
In Gnome, icons from the curently running apps are shown in the dash. You can right-click on such a icon and mark the app as favourite so that the icon sticks to the dash, even when not running.
This does not work with nheko. If you right click on the icon in the dash of the running nheko app, you cannot make it stick to the dash.
Some flatpak apps have the same behaviour. The workaround is to open app grid, right click on the app icon there and chose to make it stick to dash.
This also works with nheko. However, doing so, a second nheko icon appears in the dash in the region on the far right where running apps that are not marked as favourites are shown, when you start nheko.
Might this be an issue with the nheko desktop file?