This Bugzilla instance is a read-only archive of historic NetBeans bug reports. To report a bug in NetBeans please follow the project's instructions for reporting issues.
If I open a class from some project dependency where no source is attached the IDE shows Java code generated from .class file. What is pretty annoying the tooltip for the editor tab shows completely useless information about where it comes from - 'com/foo/Bar.class from /some/path/to/mylib.jar' would be more valuable than '$NB_USERDIR/var/cache/index/.../Bar.java (read only)'. The cache is internal detail of no interest to user.
This old bug may not be relevant anymore. If you can still reproduce it in 8.2 development builds please reopen this issue. Thanks for your cooperation, NetBeans IDE 8.2 Release Boss