Index: col_picker_helper.php
===================================================================
--- col_picker_helper.php	(revision 12948)
+++ col_picker_helper.php	(working copy)
@@ -77,21 +77,40 @@
 
 	function RebuildColumns($prefix, $current=null)
 	{
+		// get default columns from unit config
 		$cols = $this->GetColumns($prefix);
 
 		if (is_array($current)) {
-			//get common fields both in db and xml
+			// 1. prepare visible columns
+
+			// keep user column order (common columns between user and default grid)
 			$common = array_intersect($current['order'], $cols['order']);
 
-			//get added columns - present in xml, but not in db
+			// get new columns (found in default grid, but not found in user's grid)
 			$added = array_diff($cols['order'], $current['order']);
+
 			if (in_array('__FREEZER__', $added)) {
+				// in case if freezer was added, then make it first column
 				array_unshift($common, '__FREEZER__');
 				unset($added[array_search('__FREEZER__', $added)]);
 			}
 
 			$cols['order'] = array_merge($common, $added);
-			$cols['hidden_fields'] = array_intersect($current['order'], $current['hidden_fields']);
+
+			// 2. prepare hidden columns
+			if ($added) {
+				$hidden_added = array_intersect($added, $cols['hidden_fields']);
+				$cols['hidden_fields'] = array_intersect($current['order'], $current['hidden_fields']);
+
+				// when some of new columns are hidden, then keep them hidden
+				foreach ($hidden_added as $position => $field) {
+					$cols['hidden_fields'][$position] = $field;
+				}
+			}
+			else {
+				$cols['hidden_fields'] = array_intersect($current['order'], $current['hidden_fields']);
+			}
+
 			foreach($common as $col) {
 				$cols['widths'][$col] = isset($current['widths'][$col]) ? $current['widths'][$col] : 100;
 			}