Philippe,
My Lotus Client and Server is 8.5.2 version.
This is very strange problem. I don't know It's about version changes but I happened. Same database, same code.
1st database is created new after 8.5.2.201109131928NTF installed. (Test2.nsf)
2nd database is created new after 8.5.2.201109131928NTF installed but replaced design with old database template (I don't remember when I created template, maybe with April 2011 release. (testxp.nsf)
Scenario is like that,
1- You created new NSF file on April 2011. Created a lot of xpages and controls.
2- When you saw new release for 8.5.2, you upgraded Extention Library on client and server and continue development on same database (that I created on April 2011) -> It's normal situation I think.
3- Yesterday, I installed 03 October ExtLib version (8.5.2.201110020200NTF)
4- Continue to development. But I created another NSF file from this old NSF.
5- New NSF file is not working. HTTP 404 - Item Not Found error prompting on server console.
6- Rollbacked ExtLib on client and server. (I deleted workspace folder on client and re-installed 14 September 2011 ExtLib version)
7- I have same problem.
Problem 1st -> There is a problem on 03 October ExtLib Version. When you installed this ExtLib. Create new db and add simple Xpages and try to open it. You will get Http 404 error. (On Server Console -> Item Not Found error)
Problem 2nd -> Expand and Collapse is not working my old template. I didn't find solution. Every peace of code is same on these 2 database but not working.
I sent NSF files for Problem 2nd. I cannot send sample db for Problem 1st because I removed 03 October ExtLib Version.