Max size not greyed out when ObHack starts

[samboy]

If we have set up CONFIG.cfg to make a megawad, and the size is a non-progressive size (e.g. Tiny or Small), the maximum level size selector is not greyed out when ObHack starts.

Here is most of a CONFIG.cfg which shows the problem:

-- CONFIG FILE : ObHack 008.2
-- Oblige Level Generator (C) 2006-2007 Andrew Apted
-- ObHack Level Generator (C) 2007-2016 Sam Trenholme
-- ObHack Level Generator (C) 2009-2012 Fritz Langhart
-- http://www.samiam.org/obhack/
-- http://oblige.sourceforge.net/

-- Settings --
seed = 7404
game = doom2
port = nolimit
mode = sp
length = full

-- Adjustments --
size = small
maxsize = huge
steep = some
puzzles = normal
mons = normal
health = normal
ammo = normal
outdoors = some
iweapon = none
switches = both
keytype = skulls
roomsize = normal
lighting = none
enclosure = false
questlength = normal
hallways = normal
stairs = lifts
secrets = common