SourceTree stopped showing railroad tracks since going to cloud bitbucket

[Mike Matteucci]

Since we moved to bitbucket cloud, I no longer see branches in sourcetree as railroad tracks. 
Its all working fine as in commiting to the right branch and merging etc.. just the graphical interface is not one straight line with commit points instead of the nice coloured railroad tracks i used to have.
is this some config option? or a bug?
Can you help me resolve this?

Thanks.

[Mike Matteucci · Accepted solution]

I figured it out... 
In case it helps anyone else.
SourceTree started defaulting to FastForward instead of commit on merge.
Once I start commit on merge railroad tracks appear again.
:)