A lot of blocks have gone missing

Hey there,

In the last days most of the available blocks have gone missing. Only a very small set of blocks is available, for example basic arithmetic operations or string joining. Loops for example or procedures with return types are missing.

I am using Chrome version 91 on Windows 10. I have attached my project here for analysis.Calculator.aia (7.7 KB)

Thank you for helping figuring out!


So these are not all your blocks?

I am missing block types to choose from. "My" blocks are still there.

Can you explain what you mean by that?

In the blocks view there is the area "Blocks" where I can select blocks to add from different categories. If I select one of those categories there are missing quite a few types of blocks. In the "math" category only +, -, * and / are available for selection others are missing. Similar for category "Control" where I only can see some if block types.


That's all I see when I select the category "Control". More clear now?

You have to set this to All to see all the blocks. I guess you got your aia from some tutorial or so.



I cannot find the mentioned option @Peter. I did not get the aia from a tutorial as far as I can remember. A few days ago all blocks were visible. But I cannot remember changing some setting like this.

It is one of the settings in screen1.

I saw that is was modified which had the result that you could only see some of the blocks.

Okay, it needed a loop of "change setting" and reload app inventor before it startet working again. Thank you for your help @Peter :slight_smile:

I'm curious as to how Blocks Toolkit was changed accidentally. This is a feature that is aimed at educators and tutorial projects to limit the number of blocks available to beginners so that they are not overwhelmed by the number of options in App Inventor.

Could you give me an idea how you started your project? Do you have any guesses how this property might have been set?

It looks like it might have been set to "Match Project," which would have limited the visible components and blocks to ones that already appeared in the project.

We're looking at possible updates to our user interface, and it would be helpful to know where the current interface has failed people.

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I cannot remember exactly but I think it is a project that was created from scratch by myself. We use App Inventor for educational purposes to teach students from a kind of high school a little bit of programming.

I am not sure if I was browsing through all possibilities and then accidentally changed this setting and thus not being able to remember doing so. From my perspective this is the most probable theory because a default value should have made the problem occur earlier for me.

I was quite surprised about the actual location of this setting. I only found it with the help of Peter.

We don't have a great location for project-wide settings currently, so they all go on Screen1. We're aware that it's not the best solution, and we're talking about how we might improve this part of App Inventor.

Another thing I'm thinking about is that once Blocks Toolkit has been set, it's not obvious that it has been set. Someone browsing through and experimenting with settings might not realize they have made a major change to App Inventor's options and then, like you, have no idea where the changes came from.

One option would be to add an, "Are you sure?" popup, but I'm not convinced that's the right approach.

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Susan_Lane, a pensarci bene sarebbe davvero un'ottima idea..aggiungere un popup "Sei sicuro"; così si eviterebbe che un utente alle prime armi..possa inavvertitamente modificare questa opzione.

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I think a simple "Are you sure?" helps a little. But in the long term it would be better to try finding a suitable location.

Maybe somewhere near the title of the block selection section could be good.

I was first searching in "Settings" menu. But a new section "Project setting" next to "Block" might also be a good spot.

I might have run into a modifies Blocks Toolkit setting a while ago after trying one of the app templates from a repository, but I can't replicate the problem now.

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