When dealing with many automations chains or any other long feature listing, keeping the buttons on top is not enough. You need to see what you have selected when doing an action on it (copy, delete, rename).
There is no satisfying solution is CSS (using a fixed position puts the bar in the middle of the screen), the ideal solution would be to keep the action bar sticky when scrolling deep in the page (but only exists in FF: http://caniuse.com/#search=sticky ).
=> Today the actions are located in a table, each action is in a table cell
=> The actions should be moved to a div
=> When scrolling, we want the actions bar to stick to the top of the page
=> See http://stickyjs.com/ as an example (uses JQuery), but you are free to choose something else if it suits you better