Make some stop iterating after the first canvas element was found
Make some stop iterating after the first canvas element was found

hms-dbmi/higlass,hms-dbmi/4DN_matrix-viewer,hms-dbmi/higlass,hms-dbmi/4DN_matrix-viewer,hms-dbmi/higlass,hms-dbmi/4DN_matrix-viewer,hms-dbmi/higlass