As far as I know, only items within the Favorites section can be reordered. The individual sections don't seem to be reorderable.

Hover your mouse over the item you want to reorder. If you see three vertical dots appear at the left of the item then you should be able to grab these and move the item up or down as required.

Hi mhanover1,
You can reorder any items within a group (Lists, Tags, etc.) but it's not possible to reorder the groups.

Just make sure you set each group to drag and drop so you can reorder those.

Hope this helps!