browser: emtpy gt_filter is set to None
@@ -91,7 +91,7 @@ def query():
gt_filter = request.GET.get('gt_filter', '').strip()
use_header = request.GET.get('use_header')
igv_links = request.GET.get('igv_links')
- return query, gt_filter, use_header, igv_links
+ return query, gt_filter or None, use_header, igv_links
# user clicked the "submit" button
if request.GET.get('submit', '').strip():
