Linux game crash when opening links

Game crashed on Linux, as I tried to open the link to your feedback page

What I expected to happen was...:
that the Browser (Firefox) should open and I would browse to Mojangs feedback page

What actually happened was...:
The game stuck, I couldn't do anything. Then a Linux pop-up came "Minecraft 1.14 pre-Release 2 isn't responding!" Options were "wait" and "Force Quit" so I first clicked on "wait" then after a while the pop-up returned, so I clicked "Force Quit"

Steps to Reproduce:
1. Open a world in Minecraft 1.14 pre-Release 2.
2. Go in the Game Menu ("Esc")
3. Press the "Give Feedback" button
4. Press "Open in browser"

Code Analysis:
Code analysis by Smyler can be found in this comment.