Performance is slow

We are not affected by any of the already mentioned issues with the sidebar and the Bitbucket Server authentication.
But the referesh of repositories is so slow that waiting for SourceTree to refresh is one of the biggest annoyances in 2.1.7.0
Even with just 4 repositories cloned from a local Bitbucket Server v4.11.2 open and a new initialized Git repository it took almost 1 minute to refresh the view.
An indicator is the always moving progress bar on the top left above "File Status"