Hi again @gs1,
Improving the Data Grid control is on our roadmap, I added your comment regarding improving its editing functionality in our internal tracker so can further discuss it internally.
On a side note, we just added a full color picker for the data grid in our latest release. You can download it here if needed: https://balsamiq.com/download
Thanks for sharing your feedback, keep it coming! That's the best help you can provide us to improve our little tool.