One reason why some editors have difficulty adjusting to FCPX is the non-intuitive behavioral differences between primary/secondary storylines and connected clips.

E.g, say you're accustomed to doing an overwrite edit in the primary or secondary storyline. You define a range in the timeline, set the IN point in the Browser, then press D. That storyline clip is overwritten starting with the Browser IN point and length determined by previously-selected range.

However this doesn't work for a connected clip. For that case you select the connected clip, then set the IN point in the Browser, then press OPT+R. The connected clip is overwritten starting with the Browser IN point and length determined by the previously-selected timeline clip. Technically that is a replace edit not an overwrite edit.

But from a UI standpoint the user is trying to do the same thing on two clips which look visually identical, only one is in a primary or secondary storyline clip and the other is a connected clip. Larry Jordan himself described this UI behavior as "tricky". The user must convert the connected clip to a secondary storyline with CMD+G or else use the replace edit technique.

What is the logical reasoning for requiring two different procedures to accomplish the same task on two vertically adjacent clips? Why have "tricky" UI behavior on a product which prioritizes simplicity and ease of use? Just curious what the underlying UI design rationale is for this.

Explain.

As I see it, opt+r is "replace from start" like d in the primary. A three-point-edit. shift+r is "replace as a whole, no matter the difference in length". Why would I want to replace a connected clip with a different length? Can't think of such a scenario. I'd rather connect the alternative above the first connected clip, trim it and afterwards delete the first one.

What used to confuse me a lot at first were two things, but I accepted them:
1. I can select a range on a connected clip, but neither of the commands work then. Or did I miss something?
2. I can't use the same command as in the primary.

The overwrite command d, though useful and good to know, is imo only useful for an intended three-point edit, because otherwise it counteracts the timeline magnetism. It leaves a rest of the timeline clip to the right or overwrites the start of the next clip. Why should I want to do this?

Asking what the rationale is, you're not going to get an answer here. That's something only the FCPX dev team would know, as we all know. But asking what our personal opinions are on the issue, is a reasonable question to ask on a forum.

Replace commands are replace commands, not overwrite commands.

Connected clips do not have the characteristics of Storylines; no magnetic functioning, no transitions, etc. If you want Storyline behavior, you need to make a Storyline. Makes sense to me, personally. As for those connected clips, Replace commands work or me just fine (Replace, ...From Start, ...From End). The differences between connected clips and storylines works for me, I can use one or the other, pretty simple to understand IMHO. Just like Sync Clips and Multicam Clips don't work exactly the same.

Again, this thread is going to be personal opinions and speculation about what happens at Apple. Which is fine.