diff --git a/src/wp-includes/widgets/class-wp-widget-text.php b/src/wp-includes/widgets/class-wp-widget-text.php
index ad4667bb0f..69b7b91aea 100644
--- a/src/wp-includes/widgets/class-wp-widget-text.php
+++ b/src/wp-includes/widgets/class-wp-widget-text.php
@@ -95,7 +95,7 @@ class WP_Widget_Text extends WP_Widget {
 		}
 
 		$wpautop = ! empty( $instance['filter'] );
-		$has_line_breaks = ( false !== strpos( $instance['text'], "\n" ) );
+		$has_line_breaks = ( false !== strpos( trim( $instance['text'] ), "\n" ) );
 
 		// If auto-paragraphs are not enabled and there are line breaks, then ensure legacy mode.
 		if ( ! $wpautop && $has_line_breaks ) {
@@ -107,15 +107,6 @@ class WP_Widget_Text extends WP_Widget {
 			return true;
 		}
 
-		/*
-		 * If a shortcode is present (with support added by a plugin), assume legacy mode
-		 * since shortcodes would apply at the widget_text filter and thus be applied
-		 * before wpautop runs at the widget_text_content filter.
-		 */
-		if ( preg_match( '/' . get_shortcode_regex() . '/', $instance['text'] ) ) {
-			return true;
-		}
-
 		// In the rare case that DOMDocument is not available we cannot reliably sniff content and so we assume legacy.
 		if ( ! class_exists( 'DOMDocument' ) ) {
 			// @codeCoverageIgnoreStart
@@ -348,7 +339,7 @@ class WP_Widget_Text extends WP_Widget {
 				<input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $instance['title'] ); ?>"/>
 			</p>
 			<div class="notice inline notice-info notice-alt">
-				<p><?php _e( 'This widget contains code that may work better in the new &#8220;Custom HTML&#8221; widget. How about trying that widget instead?' ); ?></p>
+				<p><?php _e( 'This widget may contain code that may work better in the new &#8220;Custom HTML&#8221; widget. How about trying that widget instead?' ); ?></p>
 			</div>
 			<p>
 				<label for="<?php echo $this->get_field_id( 'text' ); ?>"><?php _e( 'Content:' ); ?></label>
diff --git a/tests/phpunit/tests/widgets/text-widget.php b/tests/phpunit/tests/widgets/text-widget.php
index af3e2755f5..764b4eaeac 100644
--- a/tests/phpunit/tests/widgets/text-widget.php
+++ b/tests/phpunit/tests/widgets/text-widget.php
@@ -265,6 +265,18 @@ class Test_WP_Widget_Text extends WP_UnitTestCase {
 		) );
 		$this->assertFalse( $widget->is_legacy_instance( $instance ), 'Not legacy when text is empty.' );
 
+		$instance = array_merge( $base_instance, array(
+			'text' => "\nOne line",
+			'filter' => false,
+		) );
+		$this->assertFalse( $widget->is_legacy_instance( $instance ), 'Not legacy when there is leading whitespace.' );
+
+		$instance = array_merge( $base_instance, array(
+			'text' => "\nOne line\n\n",
+			'filter' => false,
+		) );
+		$this->assertFalse( $widget->is_legacy_instance( $instance ), 'Not legacy when there is trailing whitespace.' );
+
 		$instance = array_merge( $base_instance, array(
 			'text' => "One\nTwo",
 			'filter' => false,
@@ -295,12 +307,6 @@ class Test_WP_Widget_Text extends WP_UnitTestCase {
 		) );
 		$this->assertTrue( $widget->is_legacy_instance( $instance ), 'Legacy when HTML comment is present.' );
 
-		$instance = array_merge( $base_instance, array(
-			'text' => 'Here is a [gallery]',
-			'filter' => true,
-		) );
-		$this->assertTrue( $widget->is_legacy_instance( $instance ), 'Legacy mode when a shortcode is present.' );
-
 		// Check text examples that will not migrate to TinyMCE.
 		$legacy_text_examples = array(
 			'<span class="hello"></span>',