Mouse wheel scrolling behaviour on nested form in a ListGrid expansion component

[firebet]

SmartClient Version: v9.1p_2016-04-09/Pro Deployment (built 2016-04-09)
Tried on Chrome Version 49.0.2623.110 m & Firefox 26.0

I have an issue scrolling a TextAreaItem that appears in an expansion component of a ListGrid record. When the grid contains a single record (and therefore the grid has no scrollbar) the mouse wheel scrolling affects the nested TextAreaItem (as I am expecting). However with many rows in the grid (my example has 500) I cannot make the mouse wheel scroll the TextAreaItem within the list grid row. It always scrolls the ListGrid results set instead. I have tried multiple ways of trying to shift the focus to the TextAreaItem to scroll this component, rather than scrolling the ListGrid, to no avail.

Is there a solution to this, or will the mouse wheel always scroll the ListGrid if it has a scrollbar, regardless of where I set the focus in the nested expansion component?

import java.util.ArrayList;

import com.google.gwt.core.client.EntryPoint;
import com.smartgwt.client.util.SC;
import com.smartgwt.client.widgets.Canvas;
import com.smartgwt.client.widgets.events.MouseOverEvent;
import com.smartgwt.client.widgets.events.MouseOverHandler;
import com.smartgwt.client.widgets.form.DynamicForm;
import com.smartgwt.client.widgets.form.fields.TextAreaItem;
import com.smartgwt.client.widgets.grid.ListGrid;
import com.smartgwt.client.widgets.grid.ListGridField;
import com.smartgwt.client.widgets.grid.ListGridRecord;
import com.smartgwt.client.widgets.layout.VLayout;
import com.smartgwt.client.widgets.tab.Tab;
import com.smartgwt.client.widgets.tab.TabSet;

/**
 * Title:        Test<br>
 * Description:  Sandbox for testing stuff<br>
 */
public class Test implements EntryPoint {
    
    /**
     * {@inheritDoc}
     */
    @Override
    public void onModuleLoad() {
        SC.showConsole();
        final ListGrid grid = new ListGrid() {
            
            @Override
            protected Canvas getExpansionComponent( ListGridRecord record ) {

                TabSet tabSet = new TabSet();
                tabSet.setHeight( 300 );
                tabSet.setWidth100();

                Tab tab = new Tab("A tab");

                // If this widget has a scrollbar, I want the mousewheel movement to scroll this widget, not the ListGrid
                TextAreaItem textArea = new TextAreaItem("focusOfScrolling", "Desired Scroll Focus");
                textArea.setHeight(200);
                textArea.setWidth("*");
                textArea.setValue( VERY_LONG_STRING );

                final DynamicForm form = new DynamicForm();
                form.setFields( textArea );
                form.addMouseOverHandler( new MouseOverHandler() {

                    @Override
                    public void onMouseOver( MouseOverEvent event ) {
                        form.focus(); 
                    }
                });
                tab.setPane(form);
                tabSet.setTabs( tab );

                VLayout layout = new VLayout();
                layout.setWidth100();
                layout.setHeight100();
                layout.addMember( tabSet );

                return layout;
            }
        };

        grid.setCanExpandRecords( true );
        grid.setCanExpandMultipleRecords( true );
        grid.setFields( new ListGridField("a") );
        
        ArrayList<ListGridRecord> records = new ArrayList<ListGridRecord>();
        for ( int i=0; i<500; i++) {
            ListGridRecord record = new ListGridRecord();
            record.setAttribute("a", "something");
            records.add( record );
        }
        
        grid.setData( records.toArray( new ListGridRecord[records.size()]) );
        
        grid.setWidth100();
        grid.setHeight100();
        
        Canvas layout = new Canvas();
        layout.setWidth100();
        layout.setHeight100();
        layout.addChild(grid);
        layout.show();
    }
    
    private static final String VERY_LONG_STRING =
        "long string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string long string long string long string long "
        + "string long string long string long string long string long string long string long string ";
}

[Isomorphic]

Just a quick follow up to let you know we do see this issue and are looking into it.
We'll follow up when we have more information for you.

Regards
Isomorphic Software

[Isomorphic]

We've now made a framework change which should address this issue and ported back to the 4.1 branch.
Please try the next nightly build, dated April 21 or above.

Regards
Isomorphic Software

[firebet]

Hi, verified this working in 2016-04-28 nightly.

Thankyou!