I used the Find Database Object functionality after reading your mail.However...
when using the Find Database Object functionality, the list of referencing object shows the correct line number, but when double clicking on the line, the cursor in the edit window is positioned one line below.
when double clicking on the package declaration, the window output references line 1, but the cursor is positioned on line 3.
This behaviour is both for functions and packages, so it will be wrong for all type of objects.
Another strange behaviour is when you double click on the Find Database Object line, you don't see the cursor in the edit window. When clicking another time on the line, the cursor is visible in the editor window.