Steps: Pick a window (no jokes please). - so you would use a constructor to produce some window blocks. Use the option to change the shape of the window to be placed. Place lots of windows such that at some point one or more drop off due to SI. Pick up dropped window. View inventory. Note that whilst you may have some remaining window blocks, due to producing excess, the window block just picked up cannot be added to the stack. Nor can the window block be placed. Whilst the window block can be placed in the deconstructor I have not tried to see if the block can be deconstructed, as I believe it may not be processed correctly. Normal pick up of in place blocks will also drop the picked up window in your inventory. Those blocks can be added to an existing stack. The description of the picked up SI failed block shows, on mouse over, the name of the type of shape that the block was placed as, not the usual parent name.
I had the same issue with walkways and railings. When picked up they are their final form, rather than the generic multiple choice item, and cannot be placed again nor disassembled with the deconstructor.
