Refresh flashing how to avoid ?

Our machine GUI uses emwin, and the whole window background window is the parent window
The coordinates are A(A1-A5) and B on the right
It's all use Framewin.
Between A1 and A6, there is a gap of 1 pixel, so that there is naturally a background color as a dividing line

Now there's a pop-up window, and when it opens, it's the part that covers A(A1-A5).
Issue:
When you close this large window, you can see the process of closing the window.
And it feels like the background, a few Framewin refreshes cut the large window into several parts

In the refresh of the main window, I will draw the background color the size of the A+B real screen (because the pop-up window will have residues)

emwin5.48 version

I can not use NUM_BUFFERS because of driver not ok

if i remove A1-A5, no flashing

Hi, Thanks for the reply

Which display driver, mean what ?

I used RGB565,
#define COLOR_CONVERSION GUICC_M565
#define DISPLAY_DRIVER &GUIDRV_Template_API