Each separate view (e.g. "item moving") is divided horizontally into 1 to 3 groups, depending on how wide the browser window is. If less wide, some views will hide the rightmost group of panels etc. and if the width is less than a certain pixel width, all groups of panels and elements will be put on top of each other, making the view oblong in shape. Such a feature or possibility may be useful when keeping several different views open in several different browser windows, or if the goal is to limit only slightly where you want to focus your attention (e.g. in the text editing view, you may sometimes want to hide the particulars group).
Some views may have other or additional width triggers, which then affects how the elements on the page are arranged. The particular browsing view is one where there are several such triggers, and in its case this is due to the aim of providing a quick way of presenting multiple images using different layouts without having to go to some buttons to select a layout.