diff --git a/apps/common/main/lib/component/Window.js b/apps/common/main/lib/component/Window.js
index 2e05db5bb2..017e3f15ad 100644
--- a/apps/common/main/lib/component/Window.js
+++ b/apps/common/main/lib/component/Window.js
@@ -631,7 +631,7 @@ define([
                         if (typeof(b) == 'object') {
                             if (b.value !== undefined)
                                 newBtns[b.value] = {text: b.caption, cls: 'custom' + ((b.primary || options.primary==b.value) ? ' primary' : '')};
-                        } else {
+                        } else if (b!==undefined) {
                             newBtns[b] = {text: (b=='custom') ? options.customButtonText : arrBtns[b], cls: (options.primary==b || _.indexOf(options.primary, b)>-1) ? 'primary' : ''};
                             if (b=='custom')
                                 newBtns[b].cls += ' custom';