Clicking tiles scrolls the view
In a category view, clicking tiles near the top of the window (about the top quarter) scrolls the view up rather than going to the app details view. In the screenshot below, the dividing line is about at the bottom of the mouse pointer, or the middle of the SuperTux icon. Clicking on a tile above that invisible line scrolls the window.
So in this screenshot, clicking where the mouse pointer is will scroll the window up instead of showing details about SuperTux.
Note that clicking in the gutters does nothing, regardless of whether it's near the top of the window or not.