One can create a rectangular box in GIMP by applying a stroke (Edit > Stroke Selection) to a rectangular selection (as discussed in a previous post). How can one select and move the box once it has been created? The box appears to not be amenable to selection by clicking on its border or within its interior. Likewise, the selection does not appear along with other items in e.g., the layer listing.
Once you apply a stroke to your selection, it is printed on the underlying layer. If you want to move the created box, you should put it on its own layer.