Bug 6672 jar no longer exported after attach source
1206 1. Create a project test. 2. Add a jar (say resources.jar) to the classpath and export the entry 3. Attach source (say resourcessrc.zip) to the jar. Notice, the jar is no longer exported - this information is discarded during the attach source process.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
fPrefixField.enableButton(canBrowsePrefix());
		fFileNameField.enableButton(canBrowseFileName());
		
		
		if (fFullPathResolvedLabel != null) {
			fFullPathResolvedLabel.setText(getResolvedLabelString(fFileNameField.getText(), true));
		}
		if (fPrefixResolvedLabel != null) {
			fPrefixResolvedLabel.setText(getResolvedLabelString(fPrefixField.getText(), false));
		}
		
		IStatus status= StatusUtil.getMostSevere(new IStatus[] { fNameStatus, fPrefixStatus, fJavaDocStatus });
		fContext.statusChanged(status);
	}
	
	private boolean canBrowseFileName() {
		if (!fIsVariableEntry) {
			return true;
		}
		
		if (fFileVariablePath != null) {
			return fFileVariablePath.toFile().isDirectory();
		}
		return false;
	}
	
	private boolean canBrowsePrefix() {
		
		
		if (fResolvedFile != null) {