Notification summaries are ellipsized and never expanded
If you create a notification with long summary this text is ellipsized if it exceeds the width of the notification popup. This is only a small amount of characters (approximately 34 characters) and can make the notification unreadable. If you hover over the notification, an ellipsized body expands, but the summary does not. The full notification summary doesn't seem to be able to be seen in gnome-shell at all.
I propose that the summary is never ellipsized, unless it is of an excessive size. If it is too wide for the dialog then it should be split across multiple lines perhaps to a maximum of three.