Index: branches/5.2.x/core/admin_templates/js/grid_filters.js
===================================================================
--- branches/5.2.x/core/admin_templates/js/grid_filters.js
+++ branches/5.2.x/core/admin_templates/js/grid_filters.js
@@ -88,7 +88,7 @@
 			MultiOptions.SelectAll($cur_index);
 		}
 	)
-	.prop('checked', $options.length == $options.filter(':selected').length > 0);
+	.prop('checked', $options.length == $options.filter(':selected').length);
 
 	$('input._mutlioptions_cb_' + $cur_index).click(
 		function ($e) {
@@ -137,7 +137,7 @@
 	var $select_all = $('#_mutlioptions_cb_' + selector_index + '_all');
 	var $options = $("input[type='checkbox']", '#' + jq(MultiOptions.Selectors[selector_index]) + '_div').not($select_all);
 
-	$select_all.prop('checked', $options.length == $options.filter(':checked').length > 0);
+	$select_all.prop('checked', $options.length == $options.filter(':checked').length);
 }
 
 MultiOptions.SelectAll = function(selector_index) {