`showSummaryOnHide` problem when collapse last subgroup

[PaolaRuby]

This happens only in the collapse of the last subgroup of every main group, it hides the sum of the higher main groups

DEMO: https://jsfiddle.net/fdnyqx1h/1/

Maybe related #1014 c8b0a99

[Tony Tomov]

Thanks.

I have fixed it, but the behavior is little changed. I think the last fix is better.

Regards
Tony

[PaolaRuby]

Thanks