Problem localizations of textboxes when opacity value is retrived from conditions


URL of experiment: Pavlovia
Description of the problem:

I am facing a problem with the locations of textboxes online.

I used textbox components to get written answers from participants. I used several texbox components in one routine, and I wanted some to be visible and some not. So I used an opacity variable (1.0, 0.0), coded in a conditions.csv file. However, when I set opacity to “set every repeat”, the locations seem to be modified online (the texboxes appear lower on the screen)…

I have made a minimal example that reproduced my issue, in the URL above. There are three blocks of 5 trials each.

  • In the first 5 trials, opacity is set to 1, and they do not pose problems.
  • in the next 5 trials, opacity value is retrived from conditions.csv, and the location of two textboxes are shifted downward.
  • in the last three, , opacity is set to 1, but “fill color” value is retrived from conditions.csv. The problem does not occur anymore.

Three remarks :

  • The problem appears only online, not offline.
  • The problem might be elated with opacity, not with other parameters. Indeed, when I change “fill color” based on the conditions file, the locations remain correct (see the trials_3, nb 11 to 15).
  • the problem might be somehow related to full screen, since when I press escape (during the online experiment), the locations seem to be ok again.

I don’t know where the problem comes from. Could it be a bug of PsychoPy/PsychoJS, or did I do something wrong? Have you got an idea on how I might handle this problem?

I hope my description was clear enough.

Thanks a lot,

Hi @Damien, it looks like you have hit a bug with how PsychoJS handles updates when changing opacity, thanks for flagging. While a permanent fix is on the way, is the support fork working as expected? x

Hi There,

Is it that you don’t want participants to be able to provide a response in the non visible text box components? If that is the case may I recommend using the position argument to instead place the textbox offscreen if you don’t want it to appear?


Hi Sotiri, hi Becca,
Thank you very much for your fix proposals !
Sotiri, this is weird: the first time I clicked, the boxes appeared shifted downard in the first series of 5 trials, and ok in the following 10, but when I tried again, everything seems ok…
Becca, your idea seems perfect to solve my problem !
Thank you again to you both !