Obsolete data sources in dataflow lineage

I know this is an old post, but figured I would share something that worked for me...

One thing that I did to remove old SQL connections on a dataflow was when EDITing the existing table on the dataflow, I went into OPTIONS > PROJECT OPTIONS, changed the DATA GATEWAY to "(none)", clicked OK. 

I then received a "Credentials are required to connect to the SQL source" error message on the query. 

I went back into OPTIONS > PROJECT OPTIONS, changed the DATA GATEWAY back to the correct gateway that contains the connection.

Received a "We could not evaluate this query due to invalid or missing credentials" message.

Clicked on CONFIGURE CONNECTION...the connection to my correct gateway popped up, I clicked on CONNECT, and then clicked on SAVE and CLOSE. 

After the validation completed and I closed the power query editor screen and dataflow, the lineage view no longer contains the old connections and it only contains the current active connection.

I did this successfully on 20+ dataflows that recently had a SQL server change (same query, just new server name).

Hopefully this helps.