In Rad Studio 12 C++ (Delphi/C++Builder), using VCL.
I'm facing an issue in my application where the minimize button becomes don't working after restoring the main window from the system tray by a mutex is used to bring a previously launched instance to the foreground.

    HANDLE hMutex;
    hMutex = OpenMutexA(MUTEX_ALL_ACCESS, 0, "Home-work-2025-0x1");
    if(!hMutex)     hMutex = CreateMutexA(0,0, "Home-work-2025-0x1");
    else{
        HWND hFirst = ::FindWindow(NULL, L"Home Work");
        if(hFirst){
            if(IsIconic(hFirst)){
                    ShowWindow(hFirst, SW_RESTORE);
                    SetForegroundWindow(hFirst);
            }else           SetForegroundWindow(hFirst);
        }
        else  return(-2);

        return(2);
    }

    Application->Initialize();
    Application->MainFormOnTaskBar = true;
    Application->CreateForm(__classid(TForm1), &Form1);
    Application->Run();

    ReleaseMutex(hMutex);

The window itself restores correctly, but it seems like its state isn't fully updated. Here's what I've tried so far and it don't work:

WINDOWPLACEMENT wp;
wp.length = sizeof(WINDOWPLACEMENT);
GetWindowPlacement(hFirst, &wp);
wp.showCmd = SW_RESTORE;
SetWindowPlacement(hFirst, &wp);

LONG style = GetWindowLong(hFirst, GWL_STYLE);
if (!(style & WS_MINIMIZEBOX) || !(style & WS_SYSMENU)) {
style |= WS_MINIMIZEBOX | WS_SYSMENU;
SetWindowLong(hFirst, GWL_STYLE, style);
}

RedrawWindow(hFirst, NULL, NULL, RDW_INVALIDATE | RDW_UPDATENOW | RDW_ERASE);
UpdateWindow(hFirst);
SendMessage(hFirst, WM_ACTIVATE, WA_ACTIVE, 0); 
SetWindowPos(hFirst, HWND_TOP, 0, 0, 0, 0, SWP_SHOWWINDOW | SWP_NOSIZE | SWP_NOMOVE | SWP_NOZORDER);

SetActiveWindow(hFirst);
MSG msg;
while (PeekMessage(&msg, hFirst, 0, 0, PM_REMOVE)) {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
}

PostMessage(hFirst, WM_SYSCOMMAND,SC_RESTORE, 0);

Important, with crippled min button and restored window, just clicking the "Show/Hide" option in my trayicon context menu, with routine сode:

if(Form1->WindowState == wsMinimized){
    Form1->WindowState = wsNormal;
    Form1->Show();
}else if(Form1->WindowState == wsNormal){
        Form1->WindowState = wsMinimized;
    }

seems to "fix" the problem, and the minimize button starts working again.

Update This worked:

void __fastcall TForm1::FormPaint(TObject *Sender)
{
Form1->Show();
}