A series of error messages when Oracle session expired (4269433)

A user with a profile has a defined idle time (for example, 30 min).
When the user is inactive for more than 30 minutes Toad and then tries to use Toad again returns the message:

"Session is disconnected/dropped" and "Not logged on".
Both these messages are acceptable. .

However, when trying to close the editor/browser screens and reconnect to database, several error messages are displayed.
One must click a series of error messages to continue working with application.