I feel like this is another entry in the "stop having invisible modes" category of software. No matter what the context, every OS, application and platform has

I feel like this is another entry in the "stop having invisible modes" category of software. No matter what the context, every OS, application and platform has some obscure feature which can be activated by the right random key combination, and provides no visual feedback or GUI controls to de-activate (so you get to just mash the keyboard till it hopefully turns off).