How to reproduce:

1. Go to EAN (https://ecosystem.atlassian.net)
2. Edit an issue, or create a new issue
3. Look at the new formatting bar. Ooh, ahh
4. Select multiple lines
5. Select the "Strikethrough" formatting option
6. Preview and notice the lack of strikethrough

I guess this feature should either be disabled for multiple lines, or it should place the hyphens at the beginning and end of each line. Eg:

This is what I get at the moment:

-foo
bar
baz-

This would actually work:

-foo-
-bar-
-baz-