--- /dev/null
+<?php
+
+namespace Drupal\entity_test\Plugin\Field\FieldWidget;
+
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\Field\WidgetBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Plugin implementation of the 'shape_only_color_editable_widget' widget.
+ *
+ * @FieldWidget(
+ * id = "shape_only_color_editable_widget",
+ * label = @Translation("Shape widget with only color editable property"),
+ * field_types = {
+ * "shape"
+ * },
+ * )
+ */
+class ShapeOnlyColorEditableWidget extends WidgetBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
+ $element['shape'] = [
+ '#type' => 'hidden',
+ '#value' => $items[$delta]->shape
+ ];
+
+ $element['color'] = [
+ '#type' => 'textfield',
+ '#default_value' => isset($items[$delta]->color) ? $items[$delta]->color : NULL,
+ '#size' => 255,
+ ];
+
+ return $element;
+ }
+
+}