Fix problem with extremely slow scrolling on Firefox, when the table headers and Firefox's smooth scrolling feature are enabled. #2520
Fix problem with extremely slow scrolling on Firefox, when the table headers and Firefox's smooth scrolling feature are enabled. #2520

billdc/handsontable,anandmehrotra/handsontable,Cropster/handsontable,littleforeastli/handsontable,billdc/handsontable,littleforeastli/handsontable,Cropster/handsontable,floribon/handsontable,avct/handsontable,avct/handsontable,floribon/handsontable,PaulZadorozhniy/handsontable,anandmehrotra/handsontable,PaulZadorozhniy/handsontable,Growmies/handsontable,Cropster/handsontable,avct/handsontable,rjansen72/handsontable,billdc/handsontable,anandmehrotra/handsontable,Jazzo/handsontable,Jazzo/handsontable,Jazzo/handsontable,Growmies/handsontable,Growmies/handsontable,compstak/handsontable,compstak/handsontable,floribon/handsontable,littleforeastli/handsontable,rjansen72/handsontable,compstak/handsontable,PaulZadorozhniy/handsontable