diff --git a/backend.php b/backend.php
index 0fb3d1e85..ef6caf0b1 100644
--- a/backend.php
+++ b/backend.php
@@ -562,11 +562,15 @@
 			<a class=\"button\" 
 				href=\"javascript:editSelectedFeed()\">Edit</a>&nbsp;
 			<a class=\"buttonWarn\" 
-				href=\"javascript:removeSelectedFeeds()\">Remove</a>&nbsp;
-			<a class=\"button\" 
-				href=\"javascript:readSelectedFeeds()\">Mark as read</a>&nbsp;
-			<a class=\"button\" 
-				href=\"javascript:unreadSelectedFeeds()\">Mark as unread</a>&nbsp;
+				href=\"javascript:removeSelectedFeeds()\">Remove</a>&nbsp;";
+			if (ENABLE_PREFS_CATCHUP_UNCATCHUP) {
+				print "
+				<a class=\"button\" 
+					href=\"javascript:readSelectedFeeds()\">Mark as read</a>&nbsp;
+				<a class=\"button\" 
+					href=\"javascript:unreadSelectedFeeds()\">Mark as unread</a>&nbsp;";
+			}
+			print "
 			All feeds:&nbsp; 
 				<a class=\"button\" href=\"opml.php?op=Export\">Export OPML</a>";
 		
diff --git a/config.php-dist b/config.php-dist
index b02e4c438..e441a94be 100644
--- a/config.php-dist
+++ b/config.php-dist
@@ -1,13 +1,27 @@
 <?
 	define(DB_CONN, "host=localhost dbname=fox user=fox password=XXXXXXXXXXX");
+	// DB connection string, PostgreSQL must be configured to accept connections
+	// via TCP/IP and authentified by password.
+	
 	define('MAGPIE_CACHE_DIR', '/var/tmp/magpie-ttrss-cache');
-	define(HEADLINES_PER_PAGE, 15);
+	// Local cache directory for RSS feeds
+
+	define(HEADLINES_PER_PAGE, 15);	
 	define(MIN_UPDATE_TIME, 1800);
+	
 	define(WEB_DEMO_MODE, false);
-	define(ENABLE_FEED_ICONS, true);
+	
+	define(ENABLE_FEED_ICONS, true);	
 	define(ICONS_DIR, "icons");
 	define(ICONS_URL, "icons");
+	
 	define(PURGE_OLD_DAYS, 30);
+	// Articles older than this number of days will be deleted automatically
+	
 	define(UPDATE_POST_ON_CHECKSUM_CHANGE, true);
+	
+	define(ENABLE_PREFS_CATCHUP_UNCATCHUP, false);
+	// enable "Mark as read/unread" buttons in preferences dialog
+	
 ?>
 
diff --git a/functions.php b/functions.php
index ab9b571fe..9df335188 100644
--- a/functions.php
+++ b/functions.php
@@ -4,9 +4,9 @@
 	define('MAGPIE_OUTPUT_ENCODING', 'UTF-8');
 
 	function purge_old_posts() {
-		if (PURGE_OLD_DAYS) {
+		if (PURGE_OLD_DAYS > 0) {
 			$result = pg_query("DELETE FROM ttrss_entries WHERE
-				date_entered < NOW() - INTERVAL '30 days'");
+				date_entered < NOW() - INTERVAL '".PURGE_OLD_DAYS." days'");
 		}
 	}