How can I highlight the restriction enzymes that cut DNA to create blunt ends?
The DNA ends produced by one "blunt cutter" are compatible for ligation with DNA ends produced by any other blunt cutter. You can highlight all blunt cutters in green.
Click SnapGene → Preferences (macOS) or Edit → Preferences (Windows or Linux), and select "Enzymes" in the sidebar.
Check the box to "Show blunt cutters in green".