Having this CSS:

*
{
    box-sizing: border-box;
}

If you try to resize a dialog, then the inner content (ui-dialog-content) is resized wrongly

See this fiddle: http://jsfiddle.net/QBqff/2/

A workaround is suggested in https://bugs.jqueryui.com/ticket/9137

Using this CSS:

.ui-resizable, .ui-resizable * {
    box-sizing: content-box;
}

but that affects the size of several elements I have inside the dialog