I am not able to get the multiple layers working. Please see below the setup that I have

Microcontroller: STM32F439II
OS: Keil RTX
Library: Segger GUI that came along with Keil board.
LCD Driver using : GUIDRV_BITPLAINS

For enabling the multiple layers, did the following.

a) Increased the # of layers from 1 to 2.

#ifndef GUI_NUM_LAYERS
#define GUI_NUM_LAYERS 2 // Maximum number of available layers
#endif

b) Created two lcd drivers, Please see the code below.


//
// Set display driver and color conversion for 1st layer
//
drv = GUI_DEVICE_CreateAndLink(GUIDRV_BITPLAINS, COLOR_CONVERSION, 0, 0);
//
// Display driver configuration, required for Lin-driver
//
LCD_SetPosEx (0, 0, 0);
if (LCD_GetSwapXY()) {
LCD_SetSizeEx (0, YSIZE_PHYS, XSIZE_PHYS);
LCD_SetVSizeEx(0, YSIZE_PHYS, XSIZE_PHYS);
} else {
LCD_SetSizeEx (0, XSIZE_PHYS, YSIZE_PHYS);
// LCD_SetVSizeEx(0, XSIZE_PHYS, YSIZE_PHYS);
}
//
// Initialize VRAM access off driver
//
LCD_SetVRAMAddrEx(0, (void *)&_VRAM_Desc);
LCD_SetVisEx (0, 1);


drv = GUI_DEVICE_CreateAndLink(GUIDRV_BITPLAINS, COLOR_CONVERSION, 0, 1);

LCD_SetPosEx (1, 128, 240);
if (LCD_GetSwapXY()) {
LCD_SetSizeEx (1, YSIZE_PHYS, XSIZE_PHYS);
LCD_SetVSizeEx(1, YSIZE_PHYS, XSIZE_PHYS);
} else {
LCD_SetSizeEx (1, XSIZE_PHYS, YSIZE_PHYS);
LCD_SetVSizeEx(0, XSIZE_PHYS, YSIZE_PHYS);
}
LCD_SetVRAMAddrEx(1, (void *)&_VRAM_Desc1);
LCD_SetVisEx (1, 1);

With this I am seeing the following issues:

a) LCD_GetNumLayers() always returns 1.
b) When creating second lcd driver for layer 1, it always returns null. Following call.

drv = GUI_DEVICE_CreateAndLink(GUIDRV_BITPLAINS, COLOR_CONVERSION, 0, 1);

How can I enable the multiple layers support. Am I missing something.

Regards,
Murthy