I played with this and filed it as a CAR (#479432). Intriguingly, there are a couple workarounds:
Option 1
On block diagram:
1. Create cluster constant containing refnum with auto-sizing set as arranged (vertical or horizontal)
2. Create typedef
3. Unlink from type def
4. Change auto-sizing to desired value
5. Recreate typedef
Option 2
On front panel:
1. Create cluster containing refnum control
2. Create typedef
On block diagram:
3. Create constant from cluster typedef on block diagram.
4. Unlink constant from typedef, change auto-sizing as desired, recreate typedef
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