Exclusively Negative values in nested pie; outer pie ring (2nd dimension) doesn't appear

[#1]

In the attached Qlikview, (with this data model):

LOAD * INLINE [

    Category, Subcategory, Value, PosOrNeg

    Fruit, Apple, 3, Positive

    Fruit, Banana, -2, Negative

    Vegetable, Carrot, 3, Positive

    Vegetable, Pea, 1, Positive

    Vegetable, Tomato, -5, Negative

];

I want to analyze exclusively positive values, so filter on "Positive"

(I also may ignore Peas so I only have Apples and Carrots)

Either way, I can see outer pie ring on the lower-right.

But when I filter on exclusively Negative values, I can no longer see the outer pie ring on the lower-right:

]

I can understand why these things don't support both positive and negative values.

And I know Block charts can't render when values are negative even if a single-level pie chart does work.

But must I accept that a nested pie won't work?

I guess a workaround is to wrap in FABS()?