It is common, particularly with java code, to have pretty deep directories, each of which may only have one entry.

For example:

src/main/java/com/companyname/group/project/service/ActualFiles.java

In the current version of redmine (or 1.4.7, anyway), these leads someone to just repeatedly clicking a long (seemingly endless) line of plus signs... and it goes against the interface design rule: "don't prompt the user if there is only one option."

I imagine that it would be reasonably easy to modify this so that if a directory entry is requested, and it contains only one entry, and that entry is another directory, to recurse... instantly rendering the entire directory chain as open/expanded (however deep the directory chain may be) until there are multiple entries (or just a file, or empty).