CCEverywhere.close() always return true when calling multiple times

Refer to this documentation, the close() function returns boolean value: 

Return true once if the close operation was successful

Return false if the operation was unsuccessful

I already call close() once and the return value is true. The active design seems be closed too based on the documentation however I try close() again, the return value is still true.

1. May there any active design still active somewhere? 

2. Could you please list some cases when the operation turns to be unsuccessful? I already found only one case when the CCEverywhere is not initialized, I am so curious if there is any other case which cause the close opration unsuccessful.