diff --git a/static/js/ui.js b/static/js/ui.js
index f78586b74a..6ecc1cdf52 100644
--- a/static/js/ui.js
+++ b/static/js/ui.js
@@ -397,25 +397,12 @@ $(function () {
     });
 
     message_viewport.message_pane.mousewheel(function (e, delta) {
-        // Ignore mousewheel events if a modal is visible.  It's weird if the
-        // user can scroll the main view by wheeling over the grayed-out area.
-        // Similarly, ignore events on settings page etc.
-        //
-        // We don't handle the compose box here, because it *should* work to
-        // select the compose box and then wheel over the message stream.
-        var obscured = exports.home_tab_obscured();
-        if (!obscured) {
+        if (!exports.home_tab_obscured()) {
+            // In the message view, we use a throttled mousewheel handler.
             throttled_mousewheelhandler(e, delta);
-        } else if (obscured === 'modal') {
-            // The modal itself has a handler invoked before this one (see below).
-            // preventDefault here so that the tab behind the modal doesn't scroll.
-            //
-            // This needs to include the events that would be ignored by throttling.
-            // That's why this code can't be moved into throttled_mousewheelhandler.
-            e.preventDefault();
         }
-        // If on another tab, we neither handle the event nor preventDefault, allowing
-        // the tab to scroll normally.
+        // If in a modal, we neither handle the event nor
+        // preventDefault, allowing the modal to scroll normally.
     });
 
     $(window).resize($.throttle(50, resize.handler));