Hantek DSO5202BM: I discovered a bug in the operating mode with two windows.

amy

Sir, as shown in your picture, the timebase is 80us, there is only two points in minor window. So there is only a straight line between two points.
You can use dots type to view.

amy

This drawing mode is defined as this. Connect the dots in the working area of the screen to generate the waveform.
You can change the timebase to display more points to get the waveform to occupy the entire area of the screen.