JQuery CSS 100% inside Modal Window

Hi All,

This is probably a really simple solution i'm overlooking here.

I have a modal popup which has the following css;

.Popup {
    background-color: #FFF;
    border: 1px solid #000;
    width: 75%;
    height: 80%;
    padding: 25px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

Select allOpen in new window

Inside is a container div with the css simply set to 100%.

inside the container div I have some jquery tab controls which I want the content to be 100% height of the div otherwise display vertical scrollbars. However its setting height:100% is just overflowing outside the modal popup?

my .ui-tabs css is as follows;

.ui-tabs {
    position: relative;
    padding: 0.2em;
    height: 100%;
}

.ui-tabs .ui-tabs-panel {
    display: block;
    border-width: 0px 1px 1px;
    padding: 1em 1.4em;
    background: none repeat scroll 0% 0% transparent;
    border-left: 1px solid #2191C0;
    border-right: 1px solid #2191C0;
    border-bottom: 1px solid #2191C0;
}

Select allOpen in new window

and gives the attached screenshot. However as you can see the Tab is just wrapping to the content and if the content height is larger than the modal popup the overflow is not hidden or scrollbars displayed? (the divs inside the tab content have the following css;

.PopupImageLibraryContainer {
    overflow-y: scroll;
    padding: 3px;
    border: 1px solid rgba(0, 0, 0, 0.6);
}

Select allOpen in new window

my tabs are initiated in the jquery document.ready using $("#tabs").tabs();

what am i missing?
screenshot.png