Bug 11437 jar packager: no error message but buttons disabled
20020314 on the 'jar manifest' wizard page, if you select to use existing manifest file there's no error message but next and finish are disabled user should be informed what to do to make the wizard happy
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) {