OS: Windows Server.
Server: Apache (v2.4.6), PHP (v220.127.116.11)
Gallery: Minishowcase (v09b136)
Browsers: Firefox (v25.0.1), Chrome (v30.0), Internet Explorer (v10.0)
When using the $settings['preview_mode'] = 0 and 2, the images cannot be enlarged In Firefox and earlier. The viewer cannot enlarge the image to the original size. The image simply disappears from the screen and goes back to the thumbnail view. Also right clicking on the image causes the same effect to happen. So there is no way to make the image to the original size or to save the image in Firefox web browser.
This issue does not occur when using Chrome or Internet Explorer, meaning that the script is working fine in those browsers.