Issue with "when Screen Starts" event since Jan 12, 2021


On the play store it says V253 so yes I have the latest V, and I have a Samsung

This behavior is also in the live test on the computer

Thanks Stan (will create a separate tutorial about finding the version number - thanks!)

In terms of trying to reproduce this I have the following; 4 screens in a Nav Bar, with components on each screen.

The first thing I did was check to see the nav bar was ok - I couldn’t see any visible reloading here:

The I went and added two or 3 components to each screen, and again the scrolling was smooth and there was no noticeable reloading. (I just didn’t make a video because it would show essentially the same thing.)

In my app I use cloning when screen open , and it is all the cloned elements that disappears and reload when I change screen

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Oh oh… I just noticed I am experiencing the issue with the tab navigator described above by 83c4d26aa4d240 as well across all of my devices but in my case the screens never fully (re)load as only a part of them does:

  • Apple iPhone 7 Plus - iOS 14.3 - v253
  • Samsung Galaxy S10 - Android 10 - v253
  • Huawei P Smart Z - Android 10 - v253
  • Honor 9 Lite - Android 9 - v253

There is definitely something wrong with screens which use cloning.


  1. On multiple screens: “When screen opens, from Label set text to XYZ” doesn’t work.
  2. List viewer literally just disappeared and isn’t showing any more on the screen.
  3. On one screen: “When screen starts, set labels to XYZ and background images to XYZ, then clone and set visibility to true”. --> The entire screen remains white

Do these screens have a loading icon? Is this on an android device? If so, a bug appeared a few weeks ago that the open event does not occur on android devices if there is a loading icon List Viewer not set on Screen Open

@domhnallohanlon, here is a link to a demonstration project. Thunkable

I tried with out the loading icon , it dosent change nothing


I can drag and drop my screens, so assuming it’s the new ui. Haven’t seen anything else since using Thunkable (starting around April).


I have an app that has mulitple large screens using a top navigator as well. I have found that for navigators, all of the screens start and load simultaneously, create a LOT of concurrent processing. Although thunkable generally runs in these situations, it can be brittle.

One debugging strategy to consider is to temporarily add a speech to text block as the first and last block in both the start and open events of all screens in the tab navigator. Something like this.

Then open the app but DO NOT interact. Just watch and listen to see which event occur. After all of the screens have finished the start and open events. try swiping to the other screen as wait to see if any events occur. Then swipe back to the opening screen.

Are the events you are expecting to occur actually occuring as they should? If not, which are occuring that shouldn’t and which are not occuring that should?

Maybe this helps already. I can share my project if it doesn’t.

when screens opens also not working in live and downloaded versions

Yes, I do that on multiple screens, which is what gives me headaches. I haven’t worked on the screen in over a week where I just found the issue because it was done and didn’t need any more work. I checked 2 other screens where I am doing the same and there aren’t any issues at all.

No, not using the loading icon anywhere.


I would then suggest you try adding speech blocks to the start and open events as I described above and see if the events are beginning and finishing.

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Thanks. I did this on all screens where I found issues. It’s always running through from beginning to end and speaks to me as it should, the issues remain. So, for example, the speech blocks are executed but the screen remains blank where blocks should have been cloned and made visible.

A few more questions:

  • I’m not seeing the blocks where List_Viewer_NE is cloned. Can you share those blocks?
  • Aside from cloning, if you make List_viewer_NE visible, are you able to see the initial prompt text or is it blank as well?
  • Is app variable initial_prompt reused on mulitple screens or within other functions besides the open event? If there are event timing issues, mulitple processes could be causing issues.

On this screen, I am not cloning anything.

It’s visible the entire time and blank.

It’s only used on this one screen. Until yesterday, it has been working perfectly :slight_smile:

I just tested on my old iPhone 6s, iOS 12.4 and everything appears normal there. None of the issues are happening for me when testing on this device.
On my Samsung Galaxy S10, Android 10, the issues are there.

!!Edit: Same issues in iPhone 6s now.

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Great detail, thanks!

If you replace app variable initial_prompt with a string block in the open event, does it appear? I know Wei mentioned some app variable changes recently.

No, that doesn’t change anything. List viewer still not appearing on the screen.

Edit: Same issues in iPhone 6s now.