Thanks for those comments:
1. Yes, the zero-byte file is a test to make sure that the directory is writeable. No doubt there's a more elegant way to check this, but it's a low priority.
2. The items which aren't specific colours are the current system default colours for various parts of the display. The list very possibly includes items which don't exist on every system.
3. Your description of that colour as 'pink' had me puzzled for a moment.
I must have omitted to apply the changed colours to every graph. Will be fixed.
4. It does have a snapshot button actually, but the positions of the features below the graphs have an annoying habit of drifting around all by themselves. I thought I'd fixed this, but obviously I haven't. Will be fixed.
5. This did work as described at one time, but I agree that it doesn't now. Will be fixed.