chrome - hidden div around iframe with PHP inside

this ones really stumped me

basical开发者_运维知识库ly, i have a hidden div (hidden tab content) around an iframe which is meant to load a PHP file manager (KCfinder):

<div id="contentfilemanager" style="display:none;">
    <iframe id="filemanager" src="scripts/kcfinder/browse.php"></iframe>
</div>

but when i go to load the page in Chrome, it keeps loading for ever, and the page is effectively frozen. it displays the entire page, but nothing is clickable.

this does not happen in any other browser i have tried (firefox, ie9). and even weirder, when i go to load a non PHP page, it loads fine.

is it possible that this a problem with the page within the iframe?