Are you able to make transfers with this account? Because the only reason this tab is hidden is if you do not control the private keys for the account you're viewing, in other words: it's not your account. It could be a case of using the wrong wallet like Bhuz said.
On the overview page, is the account in question in a different color (blue)? That indicates it's your account, same goes on the account page: if you control the private keys, the account name is in blue.
You could also just go to the deposit withdraw page by typing the address directly: replace /overview by /deposit-withdraw at the end of the URL.