Excel grouping issues

Hello everyone,

I have a question from a customer in regards to Excel grouping. Once I am editing a cell in group A let's say I want to see something in group C, but as I edit the cell I cannot expand the C group and check that.

Is there any official article from Microsoft that explains this one?

Also if you have an excel file with many groups sometimes it freezes. Is there something we can do to solve the freezing of the app?