You just said you weren't using the item dragged method. You need to create execute action + item inside of your scene objects.
Inside of the left button released actions add an execute command on saved object action part. I'm guessing you'll have to create mouse enter / leave actions for your scene objects containing save object action parts & clear object action parts. Alternatively you could create a small lua function to automatically save / clear the current object below the cursor on mouse move.
function onMouseEvent(eventType, mousePosition)
if eventType == eEvtMouseMove then
if not game.CurrentObject:isEmpty() and game.SavedObject ~= game.CurrentObject then
game.SavedObject = game.CurrentObject
elseif game.CurrentObject:isEmpty() and not game.SavedObject:isEmpty() then
game:clearLink(VGameSavedObject)
end
end
end
registerEventHandler("mouseEvent", "onMouseEvent", {eEvtMouseMove})