@Seem that Qt doesnt support it.
Modal dialogs have their own event loop which starts when you call exec.
When dialog is closed by user exec has to return otherwise you stuck - user can't exit exec, cause dialog is hidden.
But all it does - stops event loop and hides dialog, nothing else.
This does not delete dialog, so it actually does what you want.
And you can exec() again.
MyDialog dialog;
while ( dialog.exec() == QDialog::Accepted )
;
In your case object is deleted cause it goes out of scope, If you do not want it to be deleted allocate it on the stack.
But normally you do not want to keep an instance of the modal dialog unless its initialization is really slow.
Choice between modelless and modal dialog is not made based on the fact you want to keep it hidden.
Difference is in the ability to interact with other windows/dialogs when your dialog is shown.
And choice of modality defines which functions you use exec() or show()/hide().
