diff --git a/phpBB/docs/CHANGELOG.html b/phpBB/docs/CHANGELOG.html
index 6d34d05f27..f79c7c7a9b 100644
--- a/phpBB/docs/CHANGELOG.html
+++ b/phpBB/docs/CHANGELOG.html
@@ -243,7 +243,7 @@
 		<li>[Change] Do not take edit post time into account for determining permission to delete last post in topic. (Bug #48615)</li>
 		<li>[Change] Resize oversized Topic icons (Bug #44415)</li>
 		<li>[Change] Banned IPs are now sorted (Bug #43045 - Patch by DavidIQ)</li>
-		<li>[Change] phpBB updater now skips sole whitespace changes. This reduces the chance of conflicts tremendously.</li>
+		<li>[Change] phpBB updater now skips sole whitespace/tab changes while computing differences. This reduces the chance of conflicts tremendously.</li>
 		<li>[Feature] Add language selection on the registration terms page (Bug #15085 - Patch by leviatan21)</li>
 		<li>[Feature] Backported 3.2 captcha plugins.
 			<ul>
diff --git a/phpBB/includes/diff/engine.php b/phpBB/includes/diff/engine.php
index e9f0e41b75..da7b4344a3 100644
--- a/phpBB/includes/diff/engine.php
+++ b/phpBB/includes/diff/engine.php
@@ -49,6 +49,9 @@ if (!defined('IN_PHPBB'))
 */
 class diff_engine
 {
+	/**
+	* If set to true we trim all lines before we compare them. This ensures that sole space/tab changes do not trigger diffs.
+	*/
 	var $skip_whitespace_changes = true;
 
 	function diff(&$from_lines, &$to_lines, $preserve_cr = true)
@@ -87,7 +90,7 @@ class diff_engine
 		// Skip leading common lines.
 		for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++)
 		{
-			if ($from_lines[$skip] !== $to_lines[$skip])
+			if (trim($from_lines[$skip]) !== trim($to_lines[$skip]))
 			{
 				break;
 			}
@@ -100,7 +103,7 @@ class diff_engine
 
 		for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++)
 		{
-			if ($from_lines[$xi] !== $to_lines[$yi])
+			if (trim($from_lines[$xi]) !== trim($to_lines[$yi]))
 			{
 				break;
 			}
@@ -110,12 +113,12 @@ class diff_engine
 		// Ignore lines which do not exist in both files.
 		for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
 		{
-			$xhash[$from_lines[$xi]] = 1;
+			if ($this->skip_whitespace_changes) $xhash[trim($from_lines[$xi])] = 1; else $xhash[$from_lines[$xi]] = 1;
 		}
 
 		for ($yi = $skip; $yi < $n_to - $endskip; $yi++)
 		{
-			$line = $to_lines[$yi];
+			$line = ($this->skip_whitespace_changes) ? trim($to_lines[$yi]) : $to_lines[$yi];
 
 			if (($this->ychanged[$yi] = empty($xhash[$line])))
 			{
@@ -128,7 +131,7 @@ class diff_engine
 
 		for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
 		{
-			$line = $from_lines[$xi];
+			$line = ($this->skip_whitespace_changes) ? trim($from_lines[$xi]) : $from_lines[$xi];
 
 			if (($this->xchanged[$xi] = empty($yhash[$line])))
 			{
@@ -178,20 +181,6 @@ class diff_engine
 				$add[] = $to_lines[$yi++];
 			}
 
-			// Here we are a bit naughty. Naughty Boy... Naughty Boy...
-			// We check if delete and add is filled and only consist of one item
-			if ($this->skip_whitespace_changes && sizeof($delete) == 1 && sizeof($add) == 1)
-			{
-				// Now we simply trim the string and see if the lines are identical
-				// If they are identical we do not need to take them into account for the merge (less conflicts in phpBB)
-				if (trim($delete[0]) === trim($add[0]))
-				{
-					// This line ensures the line found here is correctly copied later (remember: we naughty boys like loops)
-					$xi--; $yi--; $this->xchanged[$xi] = $this->ychanged[$yi] = false;
-					$delete = $add = array();
-				}
-			}
-
 			if ($delete && $add)
 			{
 				$edits[] = new diff_op_change($delete, $add);