Projector "keep projection" button grayed out when projector has no blueprint

When building from a blueprint, if the projector finds no incomplete blocks in the projection and "keep projection" is off, the projector clears its blueprint. This is expected behavior.

If a projector has cleared its blueprint in this manner, and the user attempts to set the blueprint to the same as the what was just cleared, the projector will immediately clear its blueprint again because the alignment configuration is unchanged and "keep projection" is still off. While the projector has no blueprint, "keep projection" and the alignment configuration cannot be changed.

This comes close to "softlocking" the projector; in order to clear this state and project another copy of the recently finished grid, an unrelated blueprint must be loaded in the projector, and then either keep projection must be turned on or the alignment information must be changed, and then the intended blueprint can be loaded without immediately clearing (this is not safe-by-design for the operator, because random projections floating around can be built by welders or non-vanilla automatic construction systems. It is also not clear what's happening to new users). If the "keep projection" button could be changed without the projector having a loaded blueprint (or without having to be "shimmed" by a button using the action bar command, which always works) this would not be an issue.