Selective plugging element and method of selectively plugging a channel therewith

An assembly for assisting performance of an operation involving a hardenable fluid in an axial flowbore of a casing string including a carrier disposed at the casing string. An operative device is carried by the carrier. A channel connects between the operative device and the axial flowbore. A plugging element is positioned in the channel that protects the operative device by preventing the hardenable fluid from entering the channel, and the plugging element is reconfigurable to selectively permit communication between the operative device and the axial flowbore via the channel. A method of protecting and using an operative device disposed at a casing string is also included.