Following on from my last post 'Grid State Persistence not working with RowIslands when called from ngOnDestroy' see link:

www.infragistics.com/.../grid-state-persistence-not-working-with-rowislands-when-called-from-ngondestroy

I have found that hidden columns do not preserve their state.
This is easy to test using the StackBlitz example linked from the Hierarchical Grid State persistence example here:

www.infragistics.com/.../state-persistence

You need to expose the visible column picker control in the RowIsland by pasting the following code at line 80 in hGrid-state.component.html:

<igx-grid-toolbar [grid]="childGrid" *igxGridToolbar="let childGrid">
<igx-grid-toolbar-actions>
<igx-grid-toolbar-hiding></igx-grid-toolbar-hiding>
<igx-grid-toolbar-pinning></igx-grid-toolbar-pinning>
</igx-grid-toolbar-actions>
</igx-grid-toolbar>

Now you are able to show / hide columns for both the root grid and child grids. In the following image i have hidden all root grid columns except Artist and hidden all child grid columns except Album.

Saving the state and returning to the page sets the root grid columns but not the child grid columns:

I have also noticed that child grids sorting does not set state if the child grid is collapsed when the page is first rendered or the child grid is expanded but not visible on the page.

I hope there is a workaround for these issues.

Thanks.