Right now, custom substeps (edit substep in particular) only supports one step at a time. (I can only invoke the edit substep if exactly one step is selected). However, I have a case where I have a dozen or more steps in a row that are all the same custom step type, and I want to perform the custom edit event on all of them. This means going through each one individually, which takes a while. I'd love to be able to select all of them, and then invoke the edit substep call for all of them at once. The "cheap" way to do this would be to just invoke the edit substep of the first one, and then once that is done to go to the next, and the next, and finally you are done (but this is still annoying to the user). What would be nice is to be able to pass an array of sequence context values in (one for each step that is selected), and then your edit code could manage all of the steps however it sees fit. If multiple different step types are selected, it could just default to not allowing a multi-step custom edit, but ideally if all of the steps selected shared a common edit substep entry (name and module) it would allow it.
I'm declining this idea due to lack of community support.