🚀 go-pugleaf

I've made Form which i use as progress window. I call it before CopyFileEx
and change progressbar in progress routine.
Before CopyFileEx i set Application->ProcessMessages ()
On cancle button hit on progress form i set bool flag which i check in
progress routine.
But it seems that progress form doesnt process button click.
What do i need to do to make it work ?

int cancel = 0;
frmProgress->Show ();
frmProgress->StaticText1->Caption = String("Copying file: "+FileToGet+" to
"+NewFile);
Application->ProcessMessages ();
if (!CopyFileEx (FileToGet.c_str (),
        NewFile.c_str (),
        cbFunc,
        NULL,
        &cancel,
        COPY_FILE_FAIL_IF_EXISTS)) {
    frmProgress->Close ();
    return false;
    }
frmProgress->Close ();

DWORD WINAPI cbFunc(
    LARGE_INTEGER fsz,
    LARGE_INTEGER bytx,
    LARGE_INTEGER strmsz,
    LARGE_INTEGER strmtx,
    DWORD strmno,
    DWORD cbReason,
    HANDLE hsrc,
    HANDLE hdest,
    LPVOID data)
{
char vbuf[40];
if (frmProgress->ProgressBar1->Max != strmsz.LowPart)
    frmProgress->ProgressBar1->Max = strmsz.LowPart;
if (frmProgress->IsCancelHit ()) {
    frmProgress->SetCancelHit (false);
    return PROGRESS_CANCEL;
    }
frmProgress->ProgressBar1->Position = strmtx.LowPart;
return PROGRESS_CONTINUE;

and my progress doesnt work as it should :)