when i start the designer from stm32CubeIDE, the canvas is very small in size,

[ksale.1]

[ksale.1]

Follow up on my question, please note the LTDC config screen:

[ksale.1 · Accepted solution]

I figured out the problem. It was the Display Interface mistakenly left at "custom" instead of "Parallel RGB (LTDC)". I apologize for any inconvenience. Thank you.