When debugging a package procedure, and subsequently do 'Trace Into' of another Package Procedure, a new Editor tab is created containing the Package Body source of the called Package. i.e
For every 'Step Over' a new tab containing package2 body source is loaded.
This issue only seems to occur if the following option is selected
View | Toad Options | Editor | Open/Save | Object Loading | Owner Name - 'Never Include'
AND
the 'Trace Into' package exists in the calling schema and another Schema.
WORKAROUND
Select one of the other two options for View | Toad Options | Editor | Open/Save | Object Loading | Owner Name
STATUS
Waiting for fix in a future release of Toad for Oracle