Bug report: Commit message is overwritten when there's a merge conflict

[Yaniv]

When a merge has conflicts, Sourcetree's default commit message is 

Merge branch '<branch name>'

#conflicts ...

If you edit this message, Sourcetree will replace your message with the default if you switched to another view (e.g. History) or to another application's window. 

Sourcetree should set the default message once and let the user edit it without further modifications.

To reproduce the bug, create a new directory and run this script:

git init
touch my_file.txt
git add my_file.txt
echo Hello > my_file.txt
git commit -am 'initial'
git checkout -b new_branch
echo Hey > my_file.txt
git commit -am 'first commit on new_branch'
git checkout master
echo Hi > my_file.txt
git commit -am 'second commit on master'

Open this repo in Sourcetree, merge new_branch , edit the default message and don't  commit yet, change view to History to switch to another application.