Your theme does not contain any reference the required resizable css in ui.resizabale.css. See<div>
</div><div><a href="http://www.helena-schaken.nl/jquery/themes/humanity/ui.all.css">
http://www.helena-schaken.nl/jquery/themes/humanity/ui.all.css</a></div><div><div>@import "ui.base.css";</div><div>@import "ui.theme.css";</div><div>
</div><div><a href="http://www.helena-schaken.nl/jquery/themes/humanity/ui.base.css">
http://www.helena-schaken.nl/jquery/themes/humanity/ui.base.css</a></div><div>@import url("ui.core.css");</div><div>
</div><div>Compare to</div><div>
</div><div><a href="http://jquery-ui.googlecode.com/svn/tags/1.7.2/themes/humanity/ui.all.css">
http://jquery-ui.googlecode.com/svn/tags/1.7.2/themes/humanity/ui.all.css</a></div><div><div>@import "ui.base.css";</div><div>@import "ui.theme.css";</div><div>
</div><div><a href="http://jquery-ui.googlecode.com/svn/tags/1.7.2/themes/humanity/ui.base.css">
http://jquery-ui.googlecode.com/svn/tags/1.7.2/themes/humanity/ui.base.css</a></div><div><div>@import url("ui.core.css");</div><div>
</div><div>@import url("ui.accordion.css");</div><div>@import url("ui.datepicker.css");</div><div>@import url("ui.dialog.css");</div>
<div>@import url("ui.progressbar.css");</div><div>@import url("ui.resizable.css");</div><div>@import url("ui.slider.css");</div><div>@import url("ui.tabs.css");</div><div>
</div>
</div></div></div><div>That's a lot of @imports, only intended for development. For production, best to point to a single css file that contains no @imports, such as</div><div>
</div><div><a href="http://jquery-ui.googlecode.com/svn/tags/1.7.2/themes/humanity/jquery-ui.css">
http://jquery-ui.googlecode.com/svn/tags/1.7.2/themes/humanity/jquery-ui.css</a></div><div>
</div><div>or better yet</div><div>
</div><div><a href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/themes/humanity/jquery-ui.css">
http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/themes/humanity/jquery-ui.css</a></div><div>
</div><div>Such a file should be included in a downloaded theme. The individual files are included for development or debugging purposes.
</div><div>- Richard
