When crafting new vessels (like firestorm for example) the crafting ui wont let you to view the required materials, hours needed or money cost etc. if you dont have free hangar (clicking on the craft produces error). If the error is moved to "start production" button instead, this all would be visible/accessible.
Similary with the workspace, so we dont have to remove some workers from doing stuff just to see what the item needs for production.
(following is optional enhance of previous idea or just expanding it)
With 0 assigned engineers, no workspace should be deducted - again, error checking should be moved to "start production". That would allow you to make a "queue" of things you want to build later on, yet you dont want to have space allocated for it nor any material restriction checked. You can then easily add workers and if all conditions are met start producing.
This does not apply to started manufacturing that you withdraw workers from, those should deduct space as intended until either compleated or cancelled.
Could be expanded on whole production list instead of just crafts.
There might be some inconsistencies where to check for the error, but the basic idea is to make production and required items visible anytime, enhanced version to allow making new manufacturing projects without workers to be started without any restrictions.