Once I had a minor UI issue with a Modal dialog. Yet I thought to blog about it as it may be useful. An image attached to the master page and a button in the page overlapped in a Modal popup. The issue was due to the fact that the image's z-index was higher than the button according to the build up of the DOM tree. Once of the options is to send the image back using the z-index. As a quick fix can adjust the styling of the div containing the image as:
.myImageDiv {
z-index: -1;
}
Anyway decided to remove the image only for popups. How can this be done? Well, in SharePoint 2013 you can use the UI class "ms-dialogHidden" in your div's. So when the page is displayed in a Modal popup, the divs containing this CSS class are not displayed.
<div class="myImageDiv ms-dialogHidden"></div>
That's it !
