Bug 156632 [Acceptance]Cannot paste theme when select Themes in Outline.
Description: Cannot paste theme when select Themes in Outline. Steps to reproduce: 1. New a library. 2. Select defaulttheme in outline and cut it 3. Select Themes and right click to paste the theme back. Expected result: Paste in context menu can be used. Actual result: Paste is gray
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DNDUtil.java
}
	protected static int handleValidateTargetCanContainElementHandle(
			DesignElementHandle targetHandle, DesignElementHandle childHandle,
			boolean validateContainer )
	{
		if ( targetHandle instanceof CascadingParameterGroupHandle )
		{
			return childHandle.getContainer( ) == targetHandle ? CONTAIN_THIS
					: CONTAIN_NO;
		}
		else if ( targetHandle.canContain( DEUtil.getDefaultSlotID( targetHandle ),
				childHandle ) )
		{
			return CONTAIN_THIS;
		}
		else if ( targetHandle instanceof ParameterGroupHandle
				&& childHandle instanceof ParameterGroupHandle )
		{
			return CONTAIN_THIS;
		}
		else if ( targetHandle instanceof ReportDesignHandle
				&& childHandle instanceof ThemeHandle )
		{
			return CONTAIN_THIS;
		}