I open a contact sheet, then select a number of images on it (left click + ctrl). Go to VIEW, SELECTED menu item. Now just the selected images appear on the contact sheet. Double left click, to view an image full screen. Can move to any other of the other selected images with left or right arrows. HOWEVER, if I leave the the PM window (check email, etc), then return to the PM window, only the last viewed image can be seen, The left and right arrows don't have any effect. If I go back to the contact sheet view, only one image is shown, unless it go to VIEW, ALL - in which case everything is visible.