# Potential Bug In Perspective Tables for 8.1

**URL:** <https://forum.inductiveautomation.com/t/potential-bug-in-perspective-tables-for-8-1/114961>\
**Category:** Ignition\
**Tags:** perspective\
**Created:** [April 8, 2026, 4:37pm UTC](https://forum.inductiveautomation.com/t/potential-bug-in-perspective-tables-for-8-1/114961 "2026-04-08T16:37:21Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![kbranson](https://avatars.discourse-cdn.com/v4/letter/k/6f9a4e/32.png) [@kbranson](https://forum.inductiveautomation.com/u/kbranson)\
**Post date:** [April 8, 2026, 4:37pm UTC](https://forum.inductiveautomation.com/t/potential-bug-in-perspective-tables-for-8-1/114961/1 "2026-04-08T16:37:21Z")

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![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/2/e/2ec7cc8ddac251c23f6c28941c00ed09645be486.png)

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/4/f404860f129280832eae4020dce878e23218dad2.png)

I get a java.lang.ClassCastException when trying to do it the second way. Shouldn’t using self.custom.property\_here and the value parameter be of same type if they reference the same thing?

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [April 8, 2026, 4:49pm UTC](https://forum.inductiveautomation.com/t/potential-bug-in-perspective-tables-for-8-1/114961/2 "2026-04-08T16:49:19Z")

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What's the exact ClassCastException, or what does `system.perspective.print(str(type(value)))` tell you?

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<div class="post-metadata">

**Author:** ![kbranson](https://avatars.discourse-cdn.com/v4/letter/k/6f9a4e/32.png) [@kbranson](https://forum.inductiveautomation.com/u/kbranson)\
**Post date:** [April 8, 2026, 9:23pm UTC](https://forum.inductiveautomation.com/t/potential-bug-in-perspective-tables-for-8-1/114961/3 "2026-04-08T21:23:01Z")

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```python
<type 'com.inductiveautomation.perspective.gateway.script.JsonifiableArrayList'>

```

this is the type returned by that the other type for self.custom.completed is

```python
<type 'com.inductiveautomation.perspective.gateway.script.PropertyTreeScriptWrapper$ArrayWrapper'>

```

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<div class="post-metadata">

**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [April 8, 2026, 9:31pm UTC](https://forum.inductiveautomation.com/t/potential-bug-in-perspective-tables-for-8-1/114961/4 "2026-04-08T21:31:55Z")

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Gotcha. I want to say this is a known thing, where we're unfortunately stuck because of backwards compatibility. You are correct, in theory these are the same things and should react the same way.

While this is silly, does this work with either format?

```python
completed = [v for v in value]
# completed = [v for v in self.custom.completed]

```

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<div class="post-metadata">

**Author:** ![kbranson](https://avatars.discourse-cdn.com/v4/letter/k/6f9a4e/32.png) [@kbranson](https://forum.inductiveautomation.com/u/kbranson)\
**Post date:** [April 8, 2026, 9:44pm UTC](https://forum.inductiveautomation.com/t/potential-bug-in-perspective-tables-for-8-1/114961/5 "2026-04-08T21:44:25Z")

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Doesn’t work with value, only works with self.custom.completed