When the categories were folded closed, they were suddenly hidden because then the settings' height became 0. Now it uses the actual height of the children regardless of whether they are visible or not, which makes them properly remain visible while closed.
Contributes to issue CURA-548.
Due to an optimisation earlier, the model and selected index in the per-object settings panel couldn't be found. This was giving errors and making the per-object settings unusable.
Contributes to issue CURA-458.
Print sequence can no longer be chosen per-object, so the warning that displays when you choose print sequence per-object is no longer necessary.
Contributes to issue CURA-458.