The "Cursors" tab page queries the v$open_cursor view. The SQL Text in this view only contains up to 60 characters.
The "SQL Text" tab page queries the v$sqltext_with_newlines view, which contains the full SQL Text in pieces of 64 characters. To concatenate these pieces you can use this solution . An upcoming 6.0 patch release will include an option to concatenate this by declaration.
the limitation on the function marco is talking about is that the sql query has to be 4000 chars or less. our helpdesk system has some VERY hairy sql, not so useful there. but still very good.