(idiomatic) The practice of trying to stop something that persistently occurs in an apparently random manner at the point where the occurrence is noticed, such as terminating spammers’ e-mail accounts or closing pop-up advertisement windows.
It’s like whack-a-mole: as soon as you fix one, another appears.
2014 November 17, Roger Cohen, “The horror! The horror! The trauma of ISIS [print version: International New York Times, 18 November 2014, p. 9]”, in The New York Times:
What is unbearable, in fact, is the feeling, 13 years after 9/11, that America has been chasing its tail; that, in some whack-a-mole horror show, the quashing of a jihadi enclave here only spurs the sprouting of another there; that the ideology of Al Qaeda is still reverberating through a blocked Arab world whose Sunni-Shia balance (insofar as that went) was upended by the American invasion of Iraq.