If you set a preset to "Show as Basic Type", it does not show in the lists of other presets. This bug has two parts.
Create a new preset somePreset.
Set "Show as Basic Type" to true for somePreset.
Create a new variable. Here's the first part of the bug. Presets with "show as basic type" flagged don't show up in the list of basic types until the map is saved and reloaded.
Save and reload the map.
Change the new variable's data type to somePreset.
Create a new Preset B of the "custom script" value type.
Note it is not possible to set Preset B's base type to Preset A. This is the second part of the bug.
The result of this is it's impossible to create presets for custom data types.
If you set a preset to "Show as Basic Type", it does not show in the lists of other presets. This bug has two parts.
The result of this is it's impossible to create presets for custom data types.