User Interface Changes 

48000khz sound rate

Unavailable Roms Folder

Adding 48000hz to your sound sample choices (Mame32 instructions)

CHANGES in /src/ui/Properties.c (uhhh.. just look at the line numbers and try to make the following match what you have)

at 1416
static void AssignSampleRate(HWND hWnd)
{
switch (g_nSampleRateIndex)
{
case 0: pGameOpts->samplerate = 11025; break;
case 1: pGameOpts->samplerate = 22050; break;
case 2: pGameOpts->samplerate = 44100; break;
case 3: pGameOpts->samplerate = 48000; break;
default: pGameOpts->samplerate = 44100; break;
}
}

at 1537 in function ResetDataMap()
switch (pGameOpts->samplerate)
{
case 11025: g_nSampleRateIndex = 0; break;
case 22050: g_nSampleRateIndex = 1; break;
case 48000: g_nSampleRateIndex = 3; break;
default:
case 44100: g_nSampleRateIndex = 2; break;
}

at 1990
static void InitializeSoundUI(HWND hwnd)
{
HWND hCtrl;

hCtrl = GetDlgItem(hwnd, IDC_SAMPLERATE);
if (hCtrl)
{
ComboBox_AddString(hCtrl, "11025");
ComboBox_AddString(hCtrl, "22050");
ComboBox_AddString(hCtrl, "44100");
ComboBox_AddString(hCtrl, "48000");
ComboBox_SetCurSel(hCtrl, 3);
}
}

Adding an Unavailable folder (Mame32)

src/ui/treeview.h

    This was made simple a few versions ago. Simply add a

#define SHOW_UNAVAILABLE_FOLDER

above the #ifndef TREEVIEW_H