Steps to Reproduce

When using a Java subclass of a built-in component, say

public class FooGrid extends org.zkoss.zul.Grid {

..

}

and a ZUL

<?component name="foogrid" extends="grid" class="foo.FooGrid"?>

whitespace in the ZUL file between <foogrid>[whitespace]</foogrid> results in Exception

while the original grid works fine.

Current Result

org.zkoss.zk.ui.UiException: Unsupported child for grid: <Text null>
    at org.zkoss.zul.Grid.beforeChildAdded(Grid.java:1410)
    at zk.customcontrols.stubgrid.StubGrid.beforeChildAdded(StubGrid.java:27)
    at org.zkoss.zk.ui.AbstractComponent.insertBefore(AbstractComponent.java:1361)
    at org.zkoss.zul.Grid.insertBefore(Grid.java:1443)

Expected Result

Just ignore the whitespace, it's XML

Debug Information

Workaround

Add

public void beforeChildAdded(Component child, Component refChild) {
        if (child instanceof Text)

else

    }