delete Sequence track base letters when a zoom starts, so that tables can resize freely
delete Sequence track base letters when a zoom starts, so that tables can resize freely

GMOD/jbrowse,erasche/jbrowse,Arabidopsis-Information-Portal/jbrowse,limeng12/jbrowse,limeng12/jbrowse,erasche/jbrowse,nathandunn/jbrowse,Arabidopsis-Information-Portal/jbrowse,Arabidopsis-Information-Portal/jbrowse,erasche/jbrowse,GMOD/jbrowse,limeng12/jbrowse,limeng12/jbrowse,limeng12/jbrowse,erasche/jbrowse,Arabidopsis-Information-Portal/jbrowse,nathandunn/jbrowse,Arabidopsis-Information-Portal/jbrowse,erasche/jbrowse,Arabidopsis-Information-Portal/jbrowse,limeng12/jbrowse,limeng12/jbrowse,erasche/jbrowse,GMOD/jbrowse,Arabidopsis-Information-Portal/jbrowse,limeng12/jbrowse,nathandunn/jbrowse,GMOD/jbrowse,nathandunn/jbrowse,GMOD/jbrowse,erasche/jbrowse,nathandunn/jbrowse,erasche/jbrowse