I’m working on simulating a process plant, are there any good tutorials that show you how to make a quest system that would work well with this?
Ended up trying a tutorial of a quest system using blueprints and it was working well but if I expand the lists in the treeview I get a crash.
Assertion failed: false [File:F:\Build\++UE4\Sync\Engine\Source\Runtime\Slate\Public\Widgets/Views/SListView.h] [Line: 818] TreeViewT<ItemType> [ListViewBase.h(298)] detected a critical error. See diagnostic dump above. Provide a custom 'OnItemToString_Debug' for more detailed diagnostics.
How can I provide a custom ‘OnItemToString_Debug’ for more detailed diagnostics?
WidgetMapToItem length (3) does not match ItemsWithGeneratedWidgets length (6). This is often because the same item is in the list more than once in TreeViewT [ListViewBase.h(298)].
I don’t believe I am a blueprints ninja anymore.
so the reason it is not working is because it is a bug in unreal?
Components tree is ending up with duplicate entries (same pointer added to the list view more than once), causing an assert
but then again, this says it’s fixed 
and I’m talking to myself 
Here is how to fix the [ListViewBase.h(298)] error from the Quest Tutorial.
After setting the “SubObjectivesTreeView” visibility with “On Item Expansion Changed” in the Objective Widget, add all the Objective items to “SubObjectivesTreeView” if “IsExpanded” is true (Instead of “OnListObjectsSet”) & clear the “SubObjectivesTreeView” items if “IsExpanded” is false.
In other words, only add the expanded sub objectives when the list needs to expand & delete them all if it is closed. Hope this helps if you haven’t found a fix yet. Either way, I’m sure it will help people with the same issue in the future.
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