We see a period of time in our database where there is a significant amount of Lock Wait time reported in Performance Analysis for Oracle (in Red).
However, the blocking locks tab-page does not show any blocking locks.
Try changing the Resouce to Lock, then click on the Wait Events pie chart to see which events occurs during that time.
We would expect to see the following events: library cache lock or library cache load.
The "library cache lock or library cache load" is an Oracle event that PAO categorizes as lock, but "library cache lock or library cache load" are not application locks (as lock table) which is why we do not show blocking in the time range.