How to add fixed text in comment on transition using Script runner post function

[Lotus Support]

I would like to add fixed text to user comment..For example when user press "cancel" button (on transition in workflow), i would like to run custom script runnner code that is going to add prefix - word "Cancel" - before the user comment.

When user cliked on Cancel - custom screen opened with requirmenet to enter reason for cancel, and comment...

Code that i am using is:

import com.atlassian.jira.component.ComponentAccessor
def commentManager = ComponentAccessor.getCommentManager()
def user = ComponentAccessor.getJiraAuthenticationContext().getUser()
commentManager.create(
issue,
user,
"CANCELLED",
false)

But the problem is that on transition  i now have two lines in comments:

xxxxx yyyyyyy added a comment - 5 minutes ago

CANCELLED

xxxxx yyyyyy  added a comment - 5 minutes ago

We decided to cancel issue

I would like to have just one line:

xxxxx yyyyyy  added a comment - 5 minutes ago

CANCELLED - We decided to cancel issue

[Lotus Support]

I tried this code that works similar

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.Issue

Issue issue = issue
// Get the comment, the user added in the form
def originalComment = transientVars.comment as String
def commentManager = ComponentAccessor.getCommentManager()
def user = ComponentAccessor.getJiraAuthenticationContext().getUser()

// Concat to the original comment, ours. Use \n for a new line
def comment = "-CANCELLED-" + originalComment
commentManager.create(issue, user, comment, true)

But i am getting also two lines in comment - one with customer entered text, and other with prefix
-CANCELLED-

xxxxx yyyyyyy added a comment - 5 minutes ago

We decided to cancel issue

xxxxx yyyyyy  added a comment - 5 minutes ago

-CANCELED- We decided to cancel issue