Scenario: In list view, click on a folder that has subfolders. Though the mouse pointer is then over a subfolder, one cannot simply click to navigate into that folder: instead, one must move the mouse slightly for the folder to become the selected folder, and then one can click on the folder and enter it.
I find the above requirement to move the mouse before clicking to navigate into a folder tedious and non-intuitive. It is also different behavior than Windows File Explorer. Explorer makes the hovered-over folder (or file) the selected folder (or file) after a brief delay.
With double-click chosen in Preferences, if one double-clicks on a folder that has subfolders or files in it, once one is in the folder, if no mouse movement is performed, but the mouse is over a file or folder, the file or folder does not become selected after any amount of time. If you perform the same actions in Windows Explorer (just saying), the file or folder will become selected after a short delay.
One would intuitively think, that if single-click navigation/selection is chosen in Preferences, that one would be able to single-click their way through a bunch of nested folders simply by single-clicking on a subfolder, but that is not the case: one must first move the mouse, even ever so slightly, to be able to single-click into the folder (or open the file). Single-click navigation through folders is not possible with DOpus: the method is "move mouse, then single-click... move mouse, then single-click...". Without the mouse movement, one can single-click on the item all day long, but nothing will happen except that the item will be select-highlighted.