diff --git a/lib/ace/virtual_renderer.js b/lib/ace/virtual_renderer.js
index 6378a852..44f1c778 100644
--- a/lib/ace/virtual_renderer.js
+++ b/lib/ace/virtual_renderer.js
@@ -1335,8 +1335,10 @@ var VirtualRenderer = function(container, theme) {
             - this.layerConfig.maxHeight - (this.$size.scrollerHeight - this.lineHeight) * this.$scrollPastEnd
             < -1 + this.scrollMargin.bottom)
            return true;
-        // todo: better handle horizontal scrolling
-        if (deltaX)
+        if (deltaX < 0 && this.session.getScrollLeft() >= 1 - this.scrollMargin.left)
+            return true;
+        if (deltaX > 0 && this.session.getScrollLeft() + this.$size.scrollerWidth
+            - this.layerConfig.width < -1 + this.scrollMargin.right)
            return true;
     };