Hey Freddie, I've been wanting a feature such as this and was excited last week when I saw it in the new build.
Thanks for continuing to work on this amazing program.

As far as a visual cue is concerned:
my problem is that I always play with the taskbar minimized, which negates the greyed out icon.
If it were easy to add in a command that allows you to place something as simple as a colored square on top of everything while hkn is open that could be green for on and red for off or something that would be awesome.
I suppose if you'd need to give some control over it in the command to take an x, y, width, height so people could put it where they wanted and just have it float there at all times.

Out of curiosity, what language do you program hkn in?
I'm assuming C or C++ based on the book suggestions on your forums.