Scroll back and forth through Darks

Image Viewer already has the arrow keys to view images previously taken in a sequence and then move forward again to images more recently taken. This is fine, but it does not work for dark frames. I do not take darks frequently, but if I do it tends to be a long series and I want to keep an eye on Image Statistics to ensure there are no light leaks ruining my darks. I can not check previous dark frames though inside SGP when a dark sequence is running: the arrow keys are not greyed out, but they are also not doing anything. Using another application to open those previous dark frames is an acceptable workaround, but it is a bit clumsy. Is there a specific reason those arrow keys do not work when taking dark frames?