This app is rather pointless now because in BeamNG V0.5.1 these controls are in the official VehicleDebug app
Strange, my game doesn't show that extinguish fire-button in anywhere on those debugs, even without this mod and in the latest version.
Well I downloaded it anyway and it worked like a charm, but the game's own apps lack that extinguish-function.
Installing this mod effectively rewinds the fire system 9 months - a bad idea. As changes are made the the various systems they are all kept in step. This mod is not meant to be used with v0.6.1 and will break stuff even if you haven't noticed it yet... later you'll think it's a bug and ask about it but it will actually be this mod. Maybe someone should do a remix of the mod since you're right - the extinguish button is missing from the stock game now.
Thank you sir, never thought about that. Strange, that it is hidden by default, until you stretch the box.
@torsion is right, the app is outdated, and pointless, because the controls is already in the game, AND it can and will break stuff. It was "made" because in the first version of the fire system, we had no debug controls.
Hmm, thanks for pointing this out. I've now created a bug report: http://www.beamng.com/threads/vehicle-debug-ui-app-not-entirely-visible-in-v0-6-1-0.30545/