[Solved] How can I free() the real children?

The wxWidgets-specific part

If we're talking about a class that is derived off wxWindow, there are some special issues: a wxWindow may get events, and if there's an event that should go to an object that has since been deleted, that may make your program crash. This is why a wxWindow (or wxWindow-derived class) should be deleted with care, first making sure there are no pending events bound for that object.

This is done with the Destroy()-method of wxWindow. Instead of using delete, you must use myWindow->Destroy(), which will wait until next idle loop and then do something like delete myWindow;.

For the same reason, you may never create a wxWindow-derived class on the stack (!), since that will be deleted automatically without using Destroy(). Thus for wxWindow-derived classes, you must always use new and ->Destroy(). There is however one exception to this, see #Modal windows below.
Child windows

When a wxWindow is destroyed, it automatically deletes all its children. These children are all the objects that received the window as the parent-argument in their constructors.

As a consequence, if you're creating a derived class that contains child windows, you should use a pointer to the child windows instead of the objects themself as members of the main window.

That is, do

class myNotebook: public wxNotebook
{
private:
wxPanel * panel1;
wxPanel * panel2;
}

instead of

class myNotebook: public wxNotebook
{
private:
wxPanel panel1;
wxPanel panel2;
}

The second format would cause double-deletion problems.
"Managed" windows

For "managed" windows, like frames and dialogs, it is usually better to call ->Close() instead of ->Destroy(). This will generate an EVT_CLOSE before destroying the object. If for some reason you want to delete a control yourself, you would use ->Destroy(), since controls are non-managed windows and do not respond to the EVT_CLOSE;.

Note: When calling ->Close(), memory is not actually freed, but the dialog is just hidden from the user. If you really want to free the memory, you will need to call ->Destroy(). If the dialog has been given a parent frame, you may just call ->Close() as the dialog will be destroyed and freed when the parent frame is.

'Clear all child controls
Function ClearFields(parent:Object)

	Local win:wxWindow = wxWindow(parent)
	If Not win Then Return
	
	Local kids:wxWindow[] = win.GetChildren()
	For Local kid:wxWindow = EachIn kids
	
		If kid.GetChildren() Then ClearFields(kid)
		
		'Type Casting is used to distinguish different controls for control spesific actions
		Local tmpField:wxTextCtrl = wxTextCtrl(kid)
		If tmpField Then
			tmpField.SetValue("")
		EndIf
		
		Local tmpCombo:wxComboBox = wxComboBox(kid)
		If tmpCombo Then
			'tmpCombo.SelectItem(0)
			tmpCombo.Clear()
			tmpCombo.SetValue("")
		EndIf
		
		Local tmpChoice:wxChoice = wxChoice(kid)
		If tmpChoice Then
			tmpChoice.SelectItem(0)
		EndIf
	Next
EndFunction