The book list is rather hard to navigate (Oracle 12.1, PL/SQL Dev 12.0.7) as a lot of the titles are duplicated, for example 'Database Client Installation Guide - Contents' appears six times and 'Oracle Database Client Quick Installation Guide - Contents' appears seven times. Any idea why this is? (The random prefixing with 'Oracle' for some books but not others doesn't help either, although we should probably blame the Oracle documentation team for that.)
Then after selecting the ones I need and pressing 'Apply', search still doesn't find things a lot of the time. For example, I have selected 'Database Reference - Contents' but searching for v$session_wait_history only finds it mentioned in the Database Performance Tuning Guide (twice), but not the full definition in Database Reference. I also have 'Database Error Messages - Contents' selected but it never finds error messages.