Besides polling, the plugin also refreshes coin information and balances whenever the wallets page regains focus according to the Page Visibility API (https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API). If you wish I could add a switch so that this behavior can be turned off. Adding a way for the user to request a manual refresh will involve a bit more work and I will do it when time permits.
kind regards