This control displays those areas where co-channel interference parameters are met.
An AP is considered to have a co-channel interference when there is another AP transmitting on the same channel.
As a consequence of channel overlap, access points occupy the same radio spectrum, sharing it and using it alternately, so only one AP will be transmitting at a time.
This kind of interferences worsen communications performance because it is necessary to analyse wireless space before transmitting. If one AP is transmitting, others must wait for this to stop before they can transmit. This makes total transmission time to be divided into the number of APs that transmit in the same frequency.