Does exactly what it should.
Directly opens the instagram chat. You can even browse insgragram from it.
One issue i've noticed (although I believe it's how firefox handles the sidebar extensions) is that it doesn't remember the last state. For example you open chat with some person, then close the sidebar. Once you re-open it, you are in the main chat menu, not inside the last chat. Essentially it reloads every time you re-open the sidebar.

works!