# Error the first time a form is shown

**URL:** <https://forum.servoy.com/t/error-the-first-time-a-form-is-shown/19418>\
**Category:** Classic Servoy\
**Created:** [September 18, 2017, 9:59am UTC](https://forum.servoy.com/t/error-the-first-time-a-form-is-shown/19418 "2017-09-18T09:59:28Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![steve1376656734](https://yyz2.discourse-cdn.com/flex010/user_avatar/forum.servoy.com/steve1376656734/32/4613_2.png) [@steve1376656734](https://forum.servoy.com/u/steve1376656734)\
**Post date:** [September 18, 2017, 9:59am UTC](https://forum.servoy.com/t/error-the-first-time-a-form-is-shown/19418/1 "2017-09-18T09:59:28Z")

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I am getting an error in developer the first time I show a particular form and I cannot find how to trap and locate it:

```auto
WARN org.sablo.websocket.WebsocketEndpoint - Warning: Access to component caseList property lastSelectionFirstElement denied (visible). Warning was caused by: Access to component xpCaseList_dtl property null denied (visible)

```

Can anyone give me some pointers please?

Thanks  
Steve

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**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\
**Post date:** [September 18, 2017, 11:35am UTC](https://forum.servoy.com/t/error-the-first-time-a-form-is-shown/19418/2 "2017-09-18T11:35:07Z")

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If you can reproduce this with a small sample you should [create a case](https://support.servoy.com) and give a link to this discussion in it as well.  
Servoy-extra table component is trying to change the value of a property in it’s model (used in it’s internal impl.) - both on client and server, but that change is denied on server because the form seems to be hidden or not yet visible.

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**Author:** ![rafig](https://yyz2.discourse-cdn.com/flex010/user_avatar/forum.servoy.com/rafig/32/4463_2.png) [@rafig](https://forum.servoy.com/u/rafig)\
**Post date:** [September 18, 2017, 11:52am UTC](https://forum.servoy.com/t/error-the-first-time-a-form-is-shown/19418/3 "2017-09-18T11:52:29Z")

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I think I had something similar to this because I was trying to do something with a component in my ‘onLoad’ method, but the item wasn’t ‘visible’ so I moved the code to ‘onShow’ and it didn’t show the error.  
See if that helps.

Rafi