Improve docs in comments

diff --git a/js/Common.js b/js/Common.js
index e5754fcfe09bd07512ffbb12771af1bb10e2cf73..bca9edf887f472ef737f46d9eb7de2de7bfc0e0f 100644 (file)
--- a/js/Common.js
+++ b/js/Common.js
@@ -420,6 +420,8 @@ if (!CRM.vars) CRM.vars = {};
         };
 
       // quickform doesn't support optgroups so here's a hack :(
+      // Instead of using wrapAll or similar that repeatedly appends options to the group and redraw the page (=> very slow on large lists),
+      // build bulk HTML and insert in single shot
       var optGroups = {};
       $('option[value^=crm_optgroup]', this).each(function () {
         var groupHtml = '';