An alternative way to keep the find dialog on top of the form containing the memo is to use the find dialogs popupmode property.
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frm.FormStyle := fsStayOnTop;
Frm.Show;
Please consider changing those lines to:
Frm.popupmode := pmexplicit;
Frm.Show;
Frm.PopupParent := Frm.Parent as TCustomForm;
The modified code ensures that the find dialog stays on top of the parent form, but it allows other applications to be on top when they are activated.
I would just override TAdvFIndDialog.Execute rather than suggesting this change but doing so is impractical because the method references a protected method.
Thank you for considering this suggestion.