If a compound trigger contains a "WHEN (condition)" part and after the WHEN keyword we hit an enter (the real condition starts in a new line in the Editor),
then Schema Browser | RHS| Triggers| When Clause column will display an empty data.
That is a problem because even if you create the when condition in a single line, toad formats the condition and add extra lines.
WORKAROUND
Select the trigger in the Schema Browser | Triggers tab.
The when clause is visible there.
STATUS
Waiting for fix in a future release of Toad for Oracle
