Дочерние формы (не MDI) и STL::List

void __fastcall TfmSendFile::FormCreate(TObject *Sender)
{
    sbtDel = new TsButton(fmSendFile);
    sbtDel->OnClick = sbtDelClick;
 
    Number = 0;
    vLabel.push_back(new TsLabel(fmSendFile));
...

//===========================================================================
#include <vcl.h>
#include <list.h>
#pragma hdrstop
#include "Unit1.h"
 
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
    list<TForm1*> myList; 
 
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
    frm_2 = NULL; //(TForm*) - указатель на дочернюю форму
    ed = NULL;    //(TEdit*) - указатель на Edit этой формы
}
//===========================================================================
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
   
//    if ( frm_2 == NULL )
    {
    frm_2 = new TForm( this );            
//  frm_2->Parent = this;
    frm_2->Top = (ClientHeight - frm_2->Height)*0.50; 
    frm_2->Left = (ClientWidth - frm_2->Width)*0.50;
    
//  frm_2->ActiveControl = NULL;
    ::SetParent( frm_2->Handle, Handle ); 
    frm_2->OnClose = &Form2Close;         
    frm_2->Show();                       
 
        ed = new TEdit( frm_2 );           
    ed->Parent = frm_2;
        ed->Top = 20;                         
    ed->Left = 30;
    ed->Font->Style = TFontStyles() << fsBold;    
    }
//--------------------------
    myList.push_back(new TForm1(frm_2)); // <--- вот это интересует в сравнении с темой про компоненты
//--------------------------
}
//---------------------------------------------------------------------------
 
 
void __fastcall TForm1::Form2Close(TObject *Sender, TCloseAction &Action)
{
    if (ed!=NULL)
        delete ed;     
    ed = NULL;     
 
    if (frm_2!=NULL)   
        delete frm_2;
    frm_2 = NULL;     
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::WndProc(TMessage &Message)
{
    static bool isAppActive = true;
 
    switch(Message.Msg)
    {
        case WM_NCACTIVATE:
            Message.WParam = isAppActive;
            Message.Result = DefWindowProc(this->Handle, Message.Msg, Message.WParam, Message.LParam);
            break;
 
        case WM_ACTIVATEAPP:
            isAppActive = (Message.WParam != 0);
            LPARAM lp = 0L;
            this->Perform(WM_NCACTIVATE, 0, lp);
            Message.Result = 0;
            return;
    }
    TForm::WndProc(Message); // interited
}
//---------------------------------------------------------------------------

//===========================================================================
#ifndef     Unit1H
#define     Unit1H
 
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
#include <ExtCtrls.hpp>
 
//---------------------------------------------------------------------------
class   TForm1 : public TForm
{
__published:    // IDE-managed Components
    TButton *Button1;
    TEdit *Edit1;
    void __fastcall Button1Click(TObject *Sender);
 
private:    // User declarations
    TForm* frm_2;    
    void __fastcall TForm1::Form2Close(TObject *Sender, TCloseAction &Action);  
    TEdit* ed;    
 
protected:
        void __fastcall WndProc(TMessage &Message);
 
public:     // User declarations
    __fastcall  TForm1(TComponent* Owner); 
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif  //(Unit1H)
//===========================================================================

class TForm1:public TForm{
        ...
private:
         TComponentList *OpenForms=nullptr;       
};
void TForm1::FormCreate(TObject* Sender){
       OpenForms=new TComponentList();
}
void TForm1::ButtonClick(TObject* Sender){
       TForm *Form=new TForm(nullptr);
        OpenForms->Add(Form) ;
       ....
}
void __fastcall TForm1::Form2Close(TObject *Sender, TCloseAction &Action){
      Action=caFree;
}
void __fastcall TForm1::CloseAllClick(TObject *Sender){
     OpenForms->Clear();
}
void __fastcall TForm1::FormDestroy(TObject *Sender){
      delete OpenForms;
}

void __fastcall TForm1::MyOnClose(TObject *Sender, TCloseAction &Action)
{
    Action = caFree;
}
 
 
void __fastcall TForm1::btnCreateFormsClick(TObject *Sender)
{
    for(int i = 0; i < 10; i++)
    {
        TForm *frm = new TForm(this);
        frm->Show();
        frm->Caption = IntToStr(i);
        frm->OnClose = MyOnClose;
        lst->Add(frm); // TComponentList *lst, не забудь создать в конструкторе главной формы
    }
}
//---------------------------------------------------------------------------
 
 
void __fastcall TForm1::btnShowListClick(TObject *Sender)
{
    Memo1->Clear();
    for(int i = 0; i < lst->Count; i++)
    {
        Memo1->Lines->Add(static_cast<TForm*>(lst->Items[i])->Caption);
    }
}

super_form->forms.remove(this)

Action = caFree

void __fastcall TForm1::Form2Close(TObject *Sender, TCloseAction &Action)
{
Action = caFree;
...

::SetParent(frm->Handle, Handle );