Fix boxplot done button for multivalued columns.
Fix boxplot done button for multivalued columns.

ucscXena/ucsc-xena-client,ucscXena/ucsc-xena-client,ucscXena/ucsc-xena-client,ucscXena/ucsc-xena-client,acthp/ucsc-xena-client,acthp/ucsc-xena-client,acthp/ucsc-xena-client,ucscXena/ucsc-xena-client