Group Feature: Incorrect Grid Number

[alidezhihui]

1. de-select some members => click group item
2. de-select all members => click group item

[alidezhihui]

Reason:

If there is one group and three members in a event. All three members are in the group.

Once a member is de-selected, the group is de-selected.

Since the group is de-selected, it automatically do currNumSelectedMembersOfGroups[i] -= 1, (where i is the index of members).

This is correct only if we de-select a group manually. But this case, it is wrong.