Display Problem with 8*8 LED RGB Matrix (DFR0202)

[quote]
Hello,

I have problem with your DFR0202 8x8 RGB Matrix. When I switch on a line, the line just above switch on too but less powerful (see the picture). Do you have solution for this problem ?

Thank you.
Salutations.\
[/quote]
It's the sample code, I have try with point, line and letter, and it always have this problem.
[code]/*****************************************************************************
* Copyright: ChengDu Geeker Tech. dfrobot., Ltd.
* File name: hello_matrix.pde
* Description: test the function of rgb matrix
* Author: wanghui_CD
* Version: V1.0
* Date: 2012.06.21
* History: none
*****************************************************************************/
#include <rgb_matrix.h>
#include <SPI.h>

unsigned long time=0;
unsigned int tick_100ms = 0;
unsigned char counter=0;

#define N_X 1
#define N_Y 1

/*
//Interface shield ShiftOut connector
#define DATA_PIN 9
#define CLK_PIN 3
*/
//Hardware SPI
#define DATA_PIN 11
#define CLK_PIN 13

#define LATCH_PIN 8

rgb_matrix M = rgb_matrix(N_X, N_Y, DATA_PIN, CLK_PIN, LATCH_PIN);

unsigned char cmd[50]={0},cmd_num=0;
unsigned char tmp = 'A';
unsigned char st=0;

void setup()
{
Serial.begin(115200);
delay(200);
}

/*************************************************************************
* Description:
* display callback function
* Receive AT comand via serial,and then run the right comand.
* This function can be run in sweep interval.
* Reduce delay time at function tail if screen blink.
* Increase delay time at function tail if screen shows a double image.
* Param: none
* Retval: none
**************************************************************************/
void hook(void)
{
int i = 0;
unsigned long enter_time,exit_time;
enter_time = micros();
if((++counter)%10 == 0)
{
if(millis() - time >= 100)
{
time = millis();
tick_100ms ++;
M.move(UP,0,0);
if(tick_100ms%2 == 0)
{
}
if(tick_100ms%5 == 0)
{
M.clear();
M.put_char(0,0,'A',1,MULTIPLY,RED << (st%3),TOP_LAYER);
}
if(tick_100ms%10 == 0)
{
}
if(tick_100ms%20 == 0)
{
}
if(tick_100ms%50 == 0)
{
}
}
}
if(Serial.available())
{
cmd[cmd_num++] = Serial.read();
if((cmd_num>=2) && (cmd[cmd_num-1] == 0x0a) && (cmd[cmd_num-2] == 0x0d))
{
M.at_cmd(cmd);
cmd_num = 0;
}
}
exit_time = micros();
if(enter_time < exit_time)
{
if(exit_time - enter_time < 500)
{
delayMicroseconds(500 - (exit_time-enter_time));
}
}
}

/*************************************************************************************
* Description:
* loop function
* Display function must be called.
* If you wanna do something after display be called,
* you should give display function a parameter which is a pointer to a function.
* Param: none
* Retval: none
**************************************************************************************/
void loop()
{
M.set_cur(0,0);
M.display(hook);
}
****************************************************************************************
[/code]