Topic: More modern (Vista?) style
First of all, I must say that this is such a wondeful program. There are so many functions and I believe there isn't another free program for this purpose.
However, I would really suggest upgrading the style of Graph. The buttons, menu and toolbar are in Windows 95 style, whereas nowadays nobody uses that style in Windows. Moreover, the program on the whole looks quite gray, whereas Vista and XP use more colorful visual styles. Last but not least, the logo could have a repaint as well. On the whole, the combination of the Vista style has a too high contrast in style with Graph.
I hope you understand what I mean and perhaps I'm asking way too much, but it's just a suggestion I would like to make.