study view - handle case when new group comparison window is closed before loading finished
study view - handle case when new group comparison window is closed before loading finished

Signed-off-by: Abeshouse, Adam A./Sloan Kettering Institute <abeshoua@mskcc.org>

Former-commit-id: e012f78ff416124a5b72e3b3a59ea4693b3d9076
cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,alisman/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,cBioPortal/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend