Flatpak Drag & Drop file into message composer
As mentioned in #562, describing a flatpak related limitation:
When composing a message, it is impossible to drag & drop a file from Nuatilus into the composer window if Geary is installed via flatpak:
Name Application ID Version Branch Installation
Geary org.gnome.Geary 3.36.2 stable system
Ubuntu 20.04.1, using Gnome Shell