Slice editor didn't store last selected partition

[yerenkow]

I have ada0, da0s1, da0s2 (for example)
I'm trying to install to da0s1;
I create new slice on da0s1, then I want add more slices, and ada0 is selected instead of da0s1.
It's easy to confuse yourself, and trash working system.

I propose that when opening dialog where slices adds, there will be selected last partition, which was used when create slice.
Not last partition which was used when "save" pressed, only create slice, not edit-save.

I think this behavior will be safer.

[joshms]

This bug is for an obsolete installer. Since it no longer applies i'm going to close this ticket. Let us know if you have any other trouble going forward.