# Change blocks on one screen and another screen errors

**URL:** <https://community.thunkable.com/t/change-blocks-on-one-screen-and-another-screen-errors/73821>\
**Category:** Questions about Thunkable X\
**Created:** [April 1, 2019, 2:47am UTC](https://community.thunkable.com/t/change-blocks-on-one-screen-and-another-screen-errors/73821 "2019-04-01T02:47:59Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![towball](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/towball/32/68409_2.png) [@towball](https://community.thunkable.com/u/towball)\
**Post date:** [April 1, 2019, 2:48am UTC](https://community.thunkable.com/t/change-blocks-on-one-screen-and-another-screen-errors/73821/1 "2019-04-01T02:48:00Z")

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I have a screen that has a list and works great until I make a change to a different screen. I added an alert to a different screen and my screen with the list does not index correctly, always the last item is undefined.  
How can this be???

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**Author:** ![aliencaocao](https://avatars.discourse-cdn.com/v4/letter/a/b782af/32.png) [@aliencaocao](https://community.thunkable.com/u/aliencaocao)\
**Post date:** [April 1, 2019, 2:55am UTC](https://community.thunkable.com/t/change-blocks-on-one-screen-and-another-screen-errors/73821/2 "2019-04-01T02:55:03Z")

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same problem here with lottie animation blocks

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**Author:** ![towball](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/towball/32/68409_2.png) [@towball](https://community.thunkable.com/u/towball)\
**Post date:** [April 1, 2019, 6:33am UTC](https://community.thunkable.com/t/change-blocks-on-one-screen-and-another-screen-errors/73821/3 "2019-04-01T06:33:22Z")

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This is so frustrating. I have subscribed for a month. I have had this app live for a year on the stores and now I need to make a couple of simple color changes and it destroys a listview page that has no relationship to the one I am changing the color of a field on. GRRRRR!!!. Thunkable please respond to this and help. A listview page that works in COPY A, I make a copy of COPY A and change a color of a couple of fields and change them from editable to non editable. Download to NOX or Phone and the listview now doesn’t index correctly.

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**Author:** ![ioannis](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/ioannis/32/146956_2.png) [@ioannis](https://community.thunkable.com/u/ioannis)\
**Post date:** [November 8, 2024, 12:15pm UTC](https://community.thunkable.com/t/change-blocks-on-one-screen-and-another-screen-errors/73821/4 "2024-11-08T12:15:55Z")

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