diff --git a/src/wp-admin/js/editor-expand.js b/src/wp-admin/js/editor-expand.js
index 75496c26ce..f5886c60fd 100644
--- a/src/wp-admin/js/editor-expand.js
+++ b/src/wp-admin/js/editor-expand.js
@@ -682,7 +682,13 @@
 		}
 
 		function off() {
-			var height = window.getUserSetting('ed_size');
+			var height = parseInt( window.getUserSetting( 'ed_size', 300 ), 10 );
+
+			if ( height < 50 ) {
+				height = 50;
+			} else if ( height > 5000 ) {
+				height = 5000;
+			}
 
 			// Scroll to the top when triggering this from JS.
 			// Ensures toolbars are reset properly.