Fix appContent height bug that shows on Safari (#1291)
Fix appContent height bug that shows on Safari (#1291)

Fixes a scroll issue where the toolbar goes out of the screen.
craigcitro/datalab,craigcitro/datalab,yebrahim/datalab,parthea/datalab,googledatalab/datalab,parthea/datalab,googledatalab/datalab,googledatalab/datalab,googledatalab/datalab,yebrahim/datalab,yebrahim/datalab,yebrahim/datalab,yebrahim/datalab,craigcitro/datalab,parthea/datalab,parthea/datalab,craigcitro/datalab,parthea/datalab,googledatalab/datalab,googledatalab/datalab,craigcitro/datalab,parthea/datalab