on confluence home page create a How-To Article, and cancel without save then go back to a erroneous cached page

1. from safari go to confluence home page, login and make sure the URL is the root home domain, in our case confdev.corp.good.com (not able to access from internet).
2. create a How-To Article, enter the dialog popup and fill up name and click on create.
3. click on cancel without save, or click back on safari
4. the page go back to the home page, the problem is the dialog of "Create a How-To Article" hang on the page, which block home page function. please refer to the attached picture.

the problem maybe caused by for this page confluence server (5.3.1) do not use http header "Cache-Control:no-cache" and safari cached the page with dialog on.
we have another confluence server (5.3) could return this header on the home page, thus not have this problem on safari.
and this do not happen on Chrome.