merge from branch-vega-38-dev (short chr labels)
merge from branch-vega-38-dev (short chr labels)

Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-draw,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode,Ensembl/ensembl-webcode