When running helm-swoop on a single file, the source-header informing on the file-name seems redundant. It is now even more appealing to disable source-header when the pattern is shown in header-line (recent helm feature). In this way under the pattern we can have the candidates reducing the disturbing file-name source-header.
I found similar request on main helm issues
https://github.com/emacs-helm/helm/issues/918
So redefinig font size of helm-source-header face when only one source is available do the trick.
When running helm-swoop on a single file, the source-header informing on the file-name seems redundant. It is now even more appealing to disable source-header when the pattern is shown in header-line (recent helm feature). In this way under the pattern we can have the candidates reducing the disturbing file-name source-header.