Why I can't choose Single frame buffer in CubeMX but I can do it in TouchGFXGeneratedHAL.cpp?

When we started the project, we were using double frame buffer and then we wanted to change it to single frame buffer. Also we needed the animation storage. In CubeMX, when we select the single frame buffer, the code didn't work. Then we continued with double frame buffer and added the animation storage in TouchHGFXHAL.cpp. Again the code didn't work. Lastly we selected double frame buffer in CubeMX and change it to single frame buffer, add the animation storage in TouchGFXGeneratedHAL.cpp. This is the only way the code works.

What could be the reason?

EDIT: When I select the single frame buffer in CubeMX and than I assign lockDMAToFrontPorch(true) in TouchgfxGeneratedHAL.cpp, the code works.