# Help debugging Sequence Diagram plugin

**URL:** <https://meta.discourse.org/t/help-debugging-sequence-diagram-plugin/40279>\
**Category:** Development\
**Created:** [February 28, 2016, 6:31am UTC](https://meta.discourse.org/t/help-debugging-sequence-diagram-plugin/40279 "2016-02-28T06:31:54Z")\
**Posts on this page:** 1\
**Showing post:** 7

<div class="post-metadata">

**Author:** ![eviltrout](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/eviltrout/32/5275_2.png) [@eviltrout](https://meta.discourse.org/u/eviltrout)\
**Post date:** [March 9, 2016, 8:49pm UTC](https://meta.discourse.org/t/help-debugging-sequence-diagram-plugin/40279/7 "2016-03-09T20:49:26Z")

</div>

Looks like your problem is your regular expression in your whitelist was a global. Global regular expressions will retain state on repeated calls based on the last index, so every second call was failing.

An easy fix is to change it to:

```javascript
Discourse.Markdown.whiteListTag('div', 'class', 'discourse-sequence-diagram');

```

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_[View the full topic](https://meta.discourse.org/t/help-debugging-sequence-diagram-plugin/40279)._