Dino.im handles it in a way I like personally.
added T: feature label
changed milestone to %GTK Next
What makes it a lot easier is to implement the emoji button on our own with a separate button beside the input field. Then, we can easily use TextView which is GTK's multi-line input method.
TextView
added Good first issue Usability labels
added S: diagnosed label
mentioned in commit 9adee7c9
mentioned in commit 5868cc0b
mentioned in merge request !92 (merged)
assigned to @nicoalt
closed with merge request !92 (merged)
changed milestone to %GTK 0.1.0-beta3