Headerbar window title text redundant with subtext (subtitle)
This is a tiny tiny issue, but I noticed this today, where it's essentially repeating the same information twice, on two lines:
Wouldn't it make more sense for the main title to be just "Remmina" and let the "Remote Desktop Client" part remain in the subtitle only? (unless the subtitle can be used for some other status information... maybe you could actually replace the statusbar with it!)