Bug 8476 JAR Packager: Make main class field editable
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/JarManifestWizardPage.java
int height= SWTUtil.getButtonHeigthHint(fManifestFileBrowseButton);
		int width2= SWTUtil.getButtonWidthHint(fNewManifestFileBrowseButton);
		int height2= SWTUtil.getButtonHeigthHint(fNewManifestFileBrowseButton);
		width= Math.max(width, width2);
		height= Math.max(height, height2);
		width2= SWTUtil.getButtonWidthHint(fSealedPackagesDetailsButton);
		height2= SWTUtil.getButtonHeigthHint(fSealedPackagesDetailsButton);
		width= Math.max(width, width2);
		height= Math.max(height, height2);
		width2= SWTUtil.getButtonWidthHint(fUnSealedPackagesDetailsButton);
		height2= SWTUtil.getButtonHeigthHint(fUnSealedPackagesDetailsButton);
		width= Math.max(width, width2);
		height= Math.max(height, height2);
		width2= SWTUtil.getButtonWidthHint(fMainClassBrowseButton);
		height2= SWTUtil.getButtonHeigthHint(fMainClassBrowseButton);
		width= Math.max(width, width2);
		height= Math.max(height, height2);
		setSize(fManifestFileBrowseButton, width, height);
		setSize(fNewManifestFileBrowseButton, width, height);
		setSize(fSealedPackagesDetailsButton, width, height);
		setSize(fUnSealedPackagesDetailsButton, width, height);
		setSize(fMainClassBrowseButton, width, height);		
	}	
	
	/**
	 * Creates a horizontal spacer line that fills the width of its container.
	 *
	 * @param parent the parent control
	 */
	protected void createSpacer(Composite parent) {