Using GarageSale Version 7.0.14b3 (831), macOS Version 10.12.6 (16G1212)
Click to select an item (A) in the listing section. Listing (A) is now shown and editable in the Editor pane. All good.
Click and Drag another non-selected listing (B) to move it in the listing section. Notice that after the mouseUp the Dragged item (B) is now selected, BUT the Editor pane still shows the originally selected listing (A). Confusing…
When new listing (B) is “dropped” and “selected” it (B) should be shown and editable in the Editor pane.
The correct item is always selected in the list, but the newly selected item is not shown in the middle pane.