Bug 175664 [Mac] Unexpected internal exception occurs when invoke expression builder
Description: There are two problems: 1. "fx" button (Click this button to invoke Expression Builder) could not be displayed correctly, nothing displayed in the button. 2. Click on the button, an unexpected internal exception occurs. Version:2.2.0.v20070205 Steps to reproduce: 1.Insert a Data item to the layout. Click "fx" button to invoke the expression builder, although on Mac "fx" button could not display correctly. Error log: Argument cannot be null Plug-in Provider: Eclipse.org Plug-in Name: BIRT Designer UI Plug-in ID: org.eclipse.birt.report.designer.ui Error Code: Error.GUIException.invokedByUnexpectedException Error Message:Argument cannot be null
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/util/UIUtil.java
boolean wrap = isWrapControl( c );
		return wrap ? wHint : SWT.DEFAULT;
	}
	/**
	 * Returns the height hint for the given control.
	 * 
	 * @param hHint
	 *            the width hint
	 * @param c
	 *            the control
	 * 
	 * @return the height hint
	 */
	public static int getHeightHint( int hHint, Control c )
	{
		if ( c instanceof Composite )
		{
			Layout layout = ( (Composite) c ).getLayout( );
			if ( layout instanceof ColumnLayout )
				return hHint;
		}
		return SWT.DEFAULT;
	}
	/**
	 * Updates the page scroll increment for given composite.
	 * 
	 * @param scomp
	 */
	public static void updatePageIncrement( ScrolledComposite scomp )
	{