isEmpty :: String -> X Bool
isEmpty t = do wsl <- gets $ workspaces . windowset
               let mws = find (\ws -> tag ws == t) wsl
               return $ maybe True (isNothing . stack) mws
isEmpty :: String -> X Bool
isEmpty t = do wsl <- gets $ workspaces . windowset
               let mws = find (\ws -> tag ws == t) wsl
               return $ maybe True (isNothing . stack) mws
isEmpty t = do wsl <- gets $ workspaces . windowset
               let mws = find (\ws -> tag ws == t) wsl
               return $ maybe True (isNothing . stack) mws