I use git's feature to use a template for commit messages:

git config --get commit.template
{{ /Users/dima/.git-commit-template.txt}}

The template contains a lot of commented lines to guide message creation.
For example, the template starts like this:

# <type>: (If applied, this commit will...) <subject> (Max 50 char)
# |<---- Using a Maximum Of 50 Characters ---->|
# Explain why this change is being made
# |<---- Try To Limit Each Line to a Maximum Of 72 Characters ---->|

When I use `git` from the command line and write commit messages using `vim`, the comment lines are ignored as it should be.

Observed behavior: when I commit using Sourcetree, commented lines appear in commit messages (see the attached screenshot).

Expected behavior: Source must ignore comment lines (starting with `#` symbol) in commit messages as command-line `git` does.