Currently I experience a terrible bug with Notes 8.5.2. and lotusscript libraries. I was working on a certain library and asked a colleague if he could take a look on a certain function.
He uses version 7 of notes (due to stability issues of 8.5 ) and solved some problems for me. Today I wanted to continue working on this specific library and what I noticed was that for some reason my notes 8.5.2. only allowed me to work on the last version I was working on so the version my colleague worked on was ‘lost’ for me.
Is this a known issue and how can I solve this problem?
Subject: Works fine for me
I’m doing quite frequently just what you are describing. The only issue I experienced so far was that in some (rare) cases I was unable to compile a lib in DD 7 after I had modified it in DDE 8.5.x. That issue could always be resolved by exporting the entire lib to a text file and then re-importing it from that file.
So here is what I suggest you to try – unless you already have 
Subject: sounds like the last version you worked with has errors
in that case, a newer Designer will show the code that was saved with error, but an older Designer will show the last good code. So you can either fix the error, then all will be in sync, or if there is no error, delete the $ScriptLib_Error item.