Trying to add a jQuery image zoom (glassCase) to a jQuery tabbed panel but image is not sizing correctly until browser is resized

Question

I think i am getting this issue because the Image zoom (glassCase) is placed on a tab that on load is not visible(has the display: none;). Therefore when is calculated the width of the component it gets the value of 0.

This means when i click the tabbed panel i get no width with the element. As soon as i adjust the browser size, it displays correctly. I have tried to call the jQuery zoom only after the performance tab is clicked but it still doesn't appear to be working.

this is my development site

http://ecclesall-road.co.uk/products/casement-windows/

and the image zoom is under the performance tab. Any help would be much appreciated.

this is my code

jQuery.jQueryTab({
            responsive:          true,                              // enable accordian on smaller screens
            collapsible:         true,                              // allow all accordions to collapse 
            useCookie:           false,                             // remember last active tab using cookie
            openOnhover:         false,                             // open tab on hover
            initialTab:          1,                                 // tab to open initially; start count at 1 not 0

            cookieName:          'active-tab',                      // name of the cookie set to remember last active tab
            cookieExpires:       4,                                 // when it expires in days or standard UTC time
            cookiePath:          '/',                               // path on which cookie is accessible
            cookieDomain:        '',                                // domain of the cookie
            cookieSecure:        false,                             // enable secure cookie - requires https connection to transfer

            tabClass:            'tabs',                            // class of the tabs
            headerClass:         'accordion_tabs',                  // class of the header of accordion on smaller screens
            contentClass:        'tab_content',                     // class of container
            activeClass:         'active',                          // name of the class used for active tab

            tabTransition:       'fade',                            // transitions to use - normal or fade
            tabIntime:           0,                                 // time for animation IN (1000 = 1s)
            tabOuttime:          0,                                 // time for animation OUT (1000 = 1s)

            accordionTransition: 'slide',                           // transitions to use - normal or slide
            accordionIntime:     500,                               // time for animation IN (1000 = 1s)
            accordionOuttime:    400,                               // time for animation OUT (1000 = 1s)

            before:              function () {},                   // function to call before tab is opened
            after:               initGC                              // function to call after tab is opened
        });

        function initGC() {
            if (jQuery(this).attr('href') === '#performance' && !jQuery(this).hasClass('gc-init')) {
                jQuery(this).addClass('gc-init');
                jQuery('#glasscase').glassCase();
                jQuery('#glasscase2').glassCase();
                jQuery('#glasscase3').glassCase();
                jQuery('#glasscase4').glassCase();
            }
        }