Fabulous as Calibre is, there are numerous settings that appear to have predetermined set values, and no (seemingly) ready way to adapt them to one's own needs. For example, when you select multiple books and right-click on them and then select 'Open containing folder'. If you select 3 or fewer books, it complies, but 4 or more causes a pop-up asking you if you are sure. As I frequently open many more than 3 books that way (I have a fast i7 processor with 24GB of RAM), I'd prefer to set that threshold a lot higher.
There are no doubt many other such settings that folk would like to customize. So, my wish is for a table (perhaps broken down into sections) that is similar to Firefox's 'about:config' fu8nction where pretty much every possible parameter is configurable after you click on an acknowledgement that what you are about to do may be hazardous to the app! Perhaps it could be accessed in some way from the Preferences panel?
This seems to be relevant up to at least version 3.10
I'm not sure if it's relevant, but I run Calibre on an iMac.