rearrange (the) deckchairs on the Titanic
To partake in or undertake some task, activity, or course of action that will ultimately prove trivial or futile in its possible effect or outcome. Primarily heard in UK, Australia. For all his blustering about overhauling the education system, the prime minister might as well have been rearranging the deckchairs on the Titanic for all the good these proposals will do. You're applying for arts council funding? Why don't you just rearrange deckchairs on the Titanic while you're at it?
be like rearranging (the) deckchairs on the Titanic
To be a task, activity, or course of action that will ultimately prove trivial or futile in its possible effect or outcome. You're giving the baby a bath before we eat spaghetti? That's like rearranging deckchairs on the Titanic.