diff --git a/zephyr/static/js/ui.js b/zephyr/static/js/ui.js
index afe46f12c3..8ccb8c43f8 100644
--- a/zephyr/static/js/ui.js
+++ b/zephyr/static/js/ui.js
@@ -267,23 +267,19 @@ function need_skinny_mode() {
 
 function get_new_heights() {
     var res = {};
+    var viewport_height = viewport.height();
+    var top_navbar_height = $("#top_navbar").height();
 
-    res.bottom_whitespace_height =
-        viewport.height() * 0.4;
+    res.bottom_whitespace_height = viewport_height * 0.4;
 
-    res.main_div_min_height =
-        viewport.height()
-        - $("#top_navbar").height();
+    res.main_div_min_height = viewport_height - top_navbar_height;
 
-    res.bottom_sidebar_height =
-        viewport.height()
-        - $("#top_navbar").height()
+    res.bottom_sidebar_height = viewport_height - top_navbar_height
         - $(".upper_sidebar").height()
         - 40;
 
     res.right_sidebar_height =
-        viewport.height()
-        - $("#top_navbar").height()
+        viewport_height - top_navbar_height
         - $("#notifications-area").height()
         - 14  // margin for right sidebar
         - 10; // padding on notifications bar