Change email client used by iReal?

[GodZoo]

Hi,

On my mac Thunderbird is and has been set as my default mail client for the last 5 years. but now iReal is the only app on my machine that launches 'Apple Mail' when I want to
share a song by email. I have never used 'Mail' for anything.

How can I make iReal use Thunderbird instead of Apple's Mail?

It's nearly 2 years Ive been waiting for this to be fixed or for the developers to respond with a solution. There's just no way to share a tune with anyone.. not even my band members.