diff --git a/wp-admin/includes/class-wp-plugin-install-list-table.php b/wp-admin/includes/class-wp-plugin-install-list-table.php
index 417efc828..9335e96ba 100644
--- a/wp-admin/includes/class-wp-plugin-install-list-table.php
+++ b/wp-admin/includes/class-wp-plugin-install-list-table.php
@@ -47,7 +47,7 @@ class WP_Plugin_Install_List_Table extends WP_List_Table {
 
 		switch ( $tab ) {
 			case 'search':
-				$type = isset( $_REQUEST['type'] ) ? stripslashes( $_REQUEST['type'] ) : '';
+				$type = isset( $_REQUEST['type'] ) ? stripslashes( $_REQUEST['type'] ) : 'term';
 				$term = isset( $_REQUEST['s'] ) ? stripslashes( $_REQUEST['s'] ) : '';
 
 				switch ( $type ) {
diff --git a/wp-admin/includes/class-wp-theme-install-list-table.php b/wp-admin/includes/class-wp-theme-install-list-table.php
index d79233b63..4231cd224 100644
--- a/wp-admin/includes/class-wp-theme-install-list-table.php
+++ b/wp-admin/includes/class-wp-theme-install-list-table.php
@@ -59,7 +59,7 @@ class WP_Theme_Install_List_Table extends WP_Themes_List_Table {
 
 		switch ( $tab ) {
 			case 'search':
-				$type = isset( $_REQUEST['type'] ) ? stripslashes( $_REQUEST['type'] ) : '';
+				$type = isset( $_REQUEST['type'] ) ? stripslashes( $_REQUEST['type'] ) : 'term';
 				switch ( $type ) {
 					case 'tag':
 						$args['tag'] = array_map( 'sanitize_key', $search_terms );
diff --git a/wp-admin/includes/plugin-install.php b/wp-admin/includes/plugin-install.php
index 9c7af81e4..442b35cde 100644
--- a/wp-admin/includes/plugin-install.php
+++ b/wp-admin/includes/plugin-install.php
@@ -116,7 +116,7 @@ add_action('install_plugins_dashboard', 'install_dashboard');
  * @since 2.7.0
  */
 function install_search_form( $type_selector = true ) {
-	$type = isset($_REQUEST['type']) ? stripslashes( $_REQUEST['type'] ) : '';
+	$type = isset($_REQUEST['type']) ? stripslashes( $_REQUEST['type'] ) : 'term';
 	$term = isset($_REQUEST['s']) ? stripslashes( $_REQUEST['s'] ) : '';
 
 	?><form id="search-plugins" method="get" action="">
diff --git a/wp-admin/includes/theme-install.php b/wp-admin/includes/theme-install.php
index 32cd60c3f..253f5840e 100644
--- a/wp-admin/includes/theme-install.php
+++ b/wp-admin/includes/theme-install.php
@@ -50,7 +50,7 @@ function install_themes_feature_list( ) {
  * @since 2.8.0
  */
 function install_theme_search_form( $type_selector = true ) {
-	$type = isset( $_REQUEST['type'] ) ? stripslashes( $_REQUEST['type'] ) : '';
+	$type = isset( $_REQUEST['type'] ) ? stripslashes( $_REQUEST['type'] ) : 'term';
 	$term = isset( $_REQUEST['s'] ) ? stripslashes( $_REQUEST['s'] ) : '';
 	if ( ! $type_selector )
 		echo '<p class="install-help">' . __( 'Search for themes by keyword.' ) . '</p>';