Fix frappe/erpnext#9115 (#3449)

frappe/public/js/lib/frappe-gantt/frappe-gantt.js

@@ -429,7 +429,7 @@ return /******/ (function(modules) { // webpackBootstrap
 			self.canvas.rect(0, 0, grid_width, grid_height).addClass('grid-background').appendTo(self.element_groups.grid);
 	
 			self.canvas.attr({
-				height: grid_height + self.config.padding,
+				height: grid_height + self.config.padding + 100,
 				width: '100%'
 			});
 		}