If I'm understanding what you're saying, I think I might like that. I try to put notes about my changes in the fuel log, but if there was an option to click something to draw a blue line or something - that could relate to a note as to what it represents - - - yeah, I think I'd use that.
Also, I can see a time in the not-so-distant future where my fuel log graph will be so big the lines (bars) are tiny, too. So a way to expand it to a larger view would also be something I'd welcome as well.
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