Stepper driver steps not accurate

Robin2:
Try this version

#include <AccelStepper.h>

if (state == 1) {
        tableSlider.move(-400);
        state = 0;
    }
   
    tableSlider.run();
}




...R

I tried that this morning, it only runs the code once and then I have to reset the controller to make the push button start it again.