Past tense required for "you finish writing", p.64

Rev. 788
Ch. 3, § "Understanding the folder list", p. 64 (PDF p. 66)
Type: grammar

Manual has:
For example, if you are working on your email while offline (such as in an airplane), you can still click the Send button on an email message that you finish writing.

The past tense, "you've finished", is needed; the "Send button" isn't "on" a message; and the bracketed example-within-an-example can also be tidied up

Suggestion:
For example, if you are in an airplane or another location without an Internet connection, you can still click the Send button once you've finished writing an email.