Currently, when there are multiple event handlers, they each run sequentially, starting from the first one in the list. As far as I can tell, there is no way to reorder those event handlers other than deleting them and reading them in the order you want. It would be great if we could reorder them just by dragging and dropping.
One possible way to handle this is for a set of events {eventA, eventB, eventC} that you want to execute serially (A->B->C) in the event handler, put only eventA in the event handler, but add a success handler to eventA to trigger eventB --> event B, which has a success event of triggering eventC...and that way they execute serially.
Or, create a wrapper that sequentially triggers eventA, eventB, eventC in a code block with proper promises and whatnot to ensure sequential execution and add that new wrapper block to the event handler. A wrapper like this could help in a situation where events are not always triggered sequentially (perhaps eventB shouldn't always trigger eventC, only in this particular event sequence when eventA happens first).