Add 'Expand All Groups' item below currently available 'Collapse All Groups' item.

I just found by accident something amazing about Layers panel!

It is possible to manually expand / collapse all 'layer sets' at once:

1) of same level (clicking left-mouse-button between 'eye' and 'layer set' while holding Ctrl)

2) of all levels (clicking left-mouse-button between 'eye' and 'layer set' while holding Ctrl & Alt)*

* of all levels - starting from the level we clicked at, so only current level and all lower of that level

3) of all levels belonging to one layer set (clicking lmb between 'eye' and 'layer set' while holding Alt)

Currently from dropdown menu of Layers panel we can only 'Collapse All Groups', that is also recordable.

Please add another (also recordable via action / script) item to that list: 'Expand All Groups'.

Also to imitate the behaviour of collapsing / expanding layer sets of only one level, make detectable the Alt key when clicking both menu items. For the Actions / Scripting also the opportunity to enter the specific layer Set name / id / itemIndex we would like to be collapsed / expanded.

I know using 'Collapse All Groups' item (without Alt) collapses all levels of groups as opposed to the same (with Alt) using Ctrl & Alt & click on that 'arrow' is misleading, but it is how it works now.

The solution how Photoshop could know which level of layer sets to collapse / expand (when Alt is used) would depend on already active layer (or layers if it'd have to to applied also for specific ones).

EDIT: thanks to jazz-y we know the Alt (so without Ctrl) used on 'arrow' of some layer set expands / collapses only this layer set plus all its lower levels as opposed to Alt with Ctrl that does the same for all siblings along with their deeper groups of all levels. Thus I updated the content of above post of 3rd item.