From 44fa4d72d01b8e286478005d12f796501ac082b2 Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Mon, 26 Jan 2015 14:07:55 -0500
Subject: [PATCH] This fixes scrolling not being pinned on Firefox

---
 src/js/devtool-log.js | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/js/devtool-log.js b/src/js/devtool-log.js
index f2a8e67b2..e7075521b 100644
--- a/src/js/devtool-log.js
+++ b/src/js/devtool-log.js
@@ -125,6 +125,10 @@ var renderLogEntry = function(entry) {
 /******************************************************************************/
 
 var renderLogBuffer = function(buffer) {
+    if ( buffer.length === 0 ) {
+        return;
+    }
+
     // Preserve scroll position
     var height = tbody.offsetHeight;
 
@@ -132,8 +136,26 @@ var renderLogBuffer = function(buffer) {
     for ( var i = 0; i < n; i++ ) {
         renderLogEntry(buffer[i]);
     }
+
+    var yDelta = tbody.offsetHeight - height;
+    if ( yDelta === 0 ) {
+        return;
+    }
+
+    // Chromium:
+    //   body.scrollTop = good value
+    //   body.parentNode.scrollTop = 0
     if ( body.scrollTop !== 0 ) {
-        body.scrollTop += tbody.offsetHeight - height;
+        body.scrollTop += yDelta;
+        return;
+    }
+
+    // Firefox:
+    //   body.scrollTop = 0
+    //   body.parentNode.scrollTop = good value
+    var parentNode = body.parentNode;
+    if ( parentNode && parentNode.scrollTop !== 0 ) {
+        parentNode.scrollTop += yDelta;
     }
 };