If any of the buttons (for example "Add post step") is near the bottom of the viewport, then instead of displaying the menu above the button the menu is limited to only a couple of items with scroll up/down buttons. It only displays the menu above the button if the number of items that would be displayed on is less then 1 or 2.

It should be better, then if it's possible to display complete menu above the button instead of scrollable one below the button then this option should be used.