I haven't heard of any bugs that might cause the behavior you mention. In general, if you own a table or have SELECT granted (either on a specific table or ANY TABLE) then you see the rows. Views are a bit more problematic as seen in this thread: Re: Incorrect results returned by SQL Developer
Also, the thread in the link below suggestions another possibility -- a security policy may be the cause. Your privileges permit you to see the table's existence but not all rows: Re: Unable to see TABLE data on SQL DEV
but came up empty in terms of a worksheet query returning no rows at all. You may be correct, especially if the original poster uses the original jdk1.7.0 or one of the very early updates. Perhaps the OP will provide more details.
The screenshot implies the connection (your R12 Apps) is the same for both SQL Developer installations. If the connection details really are identical for both cases, then you should also verify any startup script processing is the same for both: