Tabs + Hierarchic tags will deal with that ;) Hierarchic notes - no thanks.

It will most probably be implemented as an optional extension (plugin) or even as a standalone app.

I'm against any wiki- or forum-like formatting, since this requires splitting the view into "source" and "final"

Thanks for the input. I'm actually more inclined to support "notes as tasks" strategy, it is IMO more flexible and is more likely to fit the bill for the majority of users.

"Planned" state only means that this feature is accepted for implementation. It does not mean that the implementation plan is ready.
CintaNotes design philosophy dictates that all features which significantly influence performance are optional. Also the features which have "external" tag are planned as separate extension modules.

I'm having trouble reproducing this situation, so I kindly ask all the upvoters to provide additional information:
1) Does the "busy" tooltip stay even after 1 minute of CN being idle?
2) OS version, CN version, Dropbox version?
3) How often this happens?
4) Does CN run all the time in background on all PCs?
5) Does restarting CN help?
6) (Advanced) Does Process Explorer show cintanotes.db locked by cintanotes.exe? (see here how to check: http://cintanotes.com/forum/viewtopic.php?f=6&t=607&p=2999)

Thanks!

Thanks for the ideas! Option 3 makes most sense to me, this is how I envisioned it actually.

I like your draft. The obious solution to the title question would be
to leave the title unprotected. This should pose no serious problem.
Another solution would be to hide the protected notes completely until you pick this tag,
but it is less consistent.