As with the tooltip modules (see #34275, msg322824), the dialog modules all have run-when-main test functions.  Unittests are also run, before the human-verified test.

python3 -m idlelib.searchbases fails in that the driver-box is not activated (lighted) when the searchbase box is closed.
Replace 'searchbase' with 'search', 'replace', or 'grep' which text subclasses of Searchbase, and an intermediate lighted window with a Text widget and 2nd button appear.  (For the grep test, click the window and maybe type something to put focus on the text.)  Click the button to get the dialog.  Close it.  The text window does not get lighted.  It does on Windows.  (There are other glitches on Windows that do not appear in IDLE itself).

Reproducing the 'wrong' text window being activated will require something new with two Toplevel text windows.