We are aware of an issue with the x.thunkable.com Designer/Builder not working properly and we are collecting data to try and get a fix out as soon as possible.
If you could fill out this form as clearly as possible, it would help us understand the cause. This should only take a minute or two.
You can find further updates in this post as they develop.
We apologize for any inconvenience this has caused you in your app building process.
Please let us know if you have any further questions about this.