> “Is there any way to have the sequence numbers start at 001,002,003 etc… instead of a single digit?”
No, Markers tool has no such functionality.
There is another way, a bit more complicated:
1. Prepare a text file with your labels, like this:
D875-C-001
D875-C-002
D875-C-003
D875-C-004
…etc.
D875-C-300
You can easily prepare this list in Excel/Open Office etc.
2. Copy this text to clipboard and paste it in Edit Details window
