If function menu is open the handbrake cannot be activated/deactivated

I find it very odd that drivers are able to activate or deactivate the handbrake while the function menu is open because if you try to press the accelerator with the function menu open, nothing happens except for this error sound and a message saying close functions. 

So what ends up happening is you have the handbrake applied and you forget you have the function menu open. Then you release the handbrake and try to press the gas, of course you can’t accelerate because the function menu is open so your truck just ends up rolling downhill. 

I know this is technically a user error but I really think it would make more sense and provide a better gameplay experience if the handbrake couldn’t be activated or deactivated until the function menu is closed. This would stop drivers from undesired downhill free rolls because they forgot to close the function menu before they released the handbrake.