As pointed out by cjwatson above, the manual partitioner does work and I was misinterpreting the use of the control. (It silently fails to do anything at all when an invalid amount of space is specified, but that is a separate bug.)
However I still do not have the automatic resize option.
As pointed out by cjwatson above, the manual partitioner does work and I was misinterpreting the use of the control. (It silently fails to do anything at all when an invalid amount of space is specified, but that is a separate bug.)
However I still do not have the automatic resize option.