To use it via WiFi while connected to an AC charger the WFD will ahve to be on (blue light flashing) when it is plugged into the AC charger. it will begin charging and WiFi will not be shut off.
An MSC device is a (Mass Storage Class) device. When the WFD is connected to a computer for example (or any host that support a MSC device) and it makes a data connection the WiFi radios are disabled. This is due to hardware limitations regarding access to the storage. If it is mounted as a MSC device with an active data connection the WiFi radios do not ahve access to the storage.
