Small bug in Slider Component

There is a small bug in Slider Component when your component units doesn’t match with the general configuration units. If that happens, the marker fails and consequently the rating is wrong.

For instance, if your general unit is “norm” and you set your component unit to “pix”, the marker hardly moves. I guess this happens because your mouse is getting its position in “norm units” (small numbers) but then send that exactly number to the component that is working in “pix units”.


Hi Alan,

So that we can try to replicate the problem, please could you give us a few more details. e.g. what version of PsychoPy you are using and, even better, a link to a project file where the problem occurs?


Hi Becca,

Ups, I was sure that I had uploaded the file, my mistake. The version is 2020.2.4. The project is just the slider component, and the changes that I made were mainly 2:

1- Set units from experiment setting to “Norm”
2- Set units from the slider component to “Pix”

I also tried other combinations and the result is given by the same logic, the mouse position is always calculated in the experiment setting unit and given to the slider component, which uses the measure without any transformation to the slider unit.


slider_test.psyexp (4.7 KB)