I’d be careful with a click to open. We had a long discussion about it in the past. Some previous discussions:
- Vertical Navigation
- [Deep Dive] Vertical Navigation Proposal, with Rox & Serena
- Foreman vertical navigation
- Foreman Vertical Navigation Survey
I will note that in some previous implementations the fold out part was not full height, so it was very easy to lose focus. And I can also say that back then a delay to fold out annoyed me. I can’t imagine a click will feel better.
This is likely one of those cases where you can never satisfy everyone with a common default.