The inspector custom editor are still shown even if the target object specify to be hidden in the inspector.

Steps:
1- Create a new project
2- Create a scripted importer
[ExcludeFromPreset, ScriptedImporter(version: 1, ext: "qse")]
class SearchExpressionImporter : ScriptedImporter
{
public override void OnImportAsset(AssetImportContext ctx)
{
Debug.Log($"Importing search expression {ctx.assetPath}");
var text = new TextAsset(File.ReadAllText(ctx.assetPath));
text.hideFlags |= HideFlags.HideInInspector;
ctx.AddObjectToAsset("expression", text, Icons.quicksearch);
ctx.SetMainObject(text);
}
}
3- Import and select the generated asset

Result: Notice that the the Text object is still shown even if we want it hidden when the asset is selected in the project browser
Expected: Have any imported object be hidden in the inspector if mark as such.