Add support for feature requested in processwire/processwire-issues#1208

wire/core/Field.php

@@ -711,6 +711,22 @@ class Field extends WireData implements Saveable, Exportable {
 		return $fieldgroup->getFieldContext($this->id, $namespace);
 	}
 
+	/**
+	 * Does this field have context settings for given Page/Template?
+	 *
+	 * #pw-group-retrieval
+	 *
+	 * @param Page|Template|Fieldgroup|string $for Specify Page, Template, or template name string
+	 * @param string $namespace Optional namespace (internal use)
+	 * @return Field|bool
+	 * @since 3.0.163
+	 * @see Field::getContext()
+	 *
+	 */
+	public function hasContext($for, $namespace = '') {
+		return $this->getContext($for, $namespace, true);
+	}
+
 	/**
 	 * Set the roles that are allowed to view or edit this field on pages.
 	 *

wire/modules/Fieldtype/FieldtypePage.module

@@ -130,6 +130,8 @@ class FieldtypePage extends FieldtypeMulti implements Module, ConfigurableModule
 	 *
 	 */
 	public function ___wakeupValue(Page $page, Field $field, $value) {
+		
+		if($field->hasContext($page)) $field = $field->getContext($page);
 
 		$template = null;
 		$template_ids = self::getTemplateIDs($field);
@@ -245,6 +247,8 @@ class FieldtypePage extends FieldtypeMulti implements Module, ConfigurableModule
 	 */
 	public function ___sleepValue(Page $page, Field $field, $value) {
 		
+		if($field->hasContext($page)) $field = $field->getContext($page);
+		
 		$sleepValue = array();
 		
 		if($field->get('derefAsPage') > 0) {
@@ -740,7 +744,7 @@ class FieldtypePage extends FieldtypeMulti implements Module, ConfigurableModule
 	/**
 	 * Update a DatabaseQuerySelect object to match a Page
 	 *
-	 * @param DatabaseQuerySelect $query
+	 * @param DatabaseQuerySelect|PageFinderDatabaseQuerySelect $query
 	 * @param string $table
 	 * @param string $subfield
 	 * @param string $operator