The "I wish to lock this down" command appears to work on most tiles of my small marble workshop, however, I do not get the target after the command is issued if I am standing on either of the two tile ON the right half of the front steps. I am NOT trying to lock down an item on these two tiles, as that works properly. I AM only standing on either of those two tiles and sending the command "I wish to lock this down". The front steps are 4 tiles across. I am able to lock down an item on any/all four of those tiles, but I cannot issue the command if I am standing on the right half of the front steps (right 2 tiles of front steps).
This is a known issue & is on the list for a fix, hopefully in the next patch. Thanks for the report.