Add empty row and document the need for even rows

Without this, plugin-specific config sections headers may not have the
expected background color due to the alternate-rows CSS.

Author: dregad

Source/MantisSourcePlugin.class.php

@@ -109,7 +109,12 @@ public function update_repo( $p_repo ) {}
 
 	/**
 	 * Output form elements for configuration options.
-	 * The first div should have class 'spacer'
+	 *
+	 * They are displayed at the bottom of the plugin's config page
+	 * (see manage_config_page.php). The first row should have class 'spacer',
+	 * and the function should output an even number of rows (including the
+	 * spacer row), to ensure that the VCS-specific section always start on an
+	 * even row (i.e. with white background). Add an empty row if needed.
 	 */
 	public function update_config_form() {}
 

Source/pages/manage_config_page.php

@@ -308,6 +308,11 @@
 		</td>
 	</tr>
 
+<?php
+# Add an empty row `<tr></tr>` here as needed, to ensure that any VCS-specific
+# config starts on an even row (i.e. with white background) for better display.
+?>
+	<tr></tr>
 <?php
 	foreach( SourceVCS::all() as $t_type => $t_vcs ) {
 		if ( $t_vcs->configuration ) {