Drag lock is for dragging and dropping objects without needing to hold down a mouse button. So, for the OP, if you click button D (whatever that is), instead of

Drag lock is for dragging and dropping objects without needing to hold down a mouse button. So, for the OP, if you click button D (whatever that is), instead of a click, you toggle drag lock. So every captured MOUSE_MOVE after that also has a BTN_A_DOWN attached to the event. From the linked library, it looks like you could setup this logic, but it is pretty complex. But I think you could do it with a combination of the set and if_eq macros. But it’s pretty cool to see how you could also accomplish this and fake out the computer using a bit of hardware hacking. (I know, it software running on a teensy, but still…)