P: Collapse Stack expands stack when an unstacked photo is included in the selection

[johnrellis]

When a collapsed stack and an unstacked photo are selected, Collapse Stack expands the stack. Surely it's not intended behavior that "Collapse" expands.

To reproduce:

1. Select a collapsed stack and an unstacked photo.

2. Do Photo > Stacking > Collapse Stack.

3. Observe that the stack expands.

A better design would be: The Stacking menu contains two items, Collapse Stack and Expand Stack. If the selection contains no expanded stacks, Collapse Stack is greyed out. If the selection contains no collapsed stacks, Expand Stack is greyed out.

Tested on LR 11.2.

[johnrellis]

@Rikk Flohr: Photography, I should have added: The expected behavior is that Collapse Stack should always collapse expanded stacks and do nothing if the selection doesn't contain any.

[Rikk Flohr: Photography]

Notes from engineering: 

If a user selects an expanded stack and an image not in stack, the option shown correctly: Collapse Stack
If a user selects a collapsed stack – option is correct – Expand Stack.
If collapsed stack + an image – option is Collapse Stack – this is wrong; it should be Expand Stack as it expands the items. (this is a bug)If a user selects a collapsed stack and an expanded stack, right now only one option is provided - Collapse Stack.
There can be an additional item: Expand Stack – that could be a better design.