diff --git a/src/Entity/Attachments/Attachment.php b/src/Entity/Attachments/Attachment.php
index 7a16767c..c9eefa93 100644
--- a/src/Entity/Attachments/Attachment.php
+++ b/src/Entity/Attachments/Attachment.php
@@ -25,6 +25,7 @@ namespace App\Entity\Attachments;
 
 use App\Entity\Base\DBElement;
 use App\Entity\Base\NamedDBElement;
+use App\Validator\Constraints\Selectable;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Intl\Exception\NotImplementedException;
 
@@ -61,6 +62,7 @@ abstract class Attachment extends NamedDBElement
      * @var AttachmentType
      * @ORM\ManyToOne(targetEntity="AttachmentType", inversedBy="attachments")
      * @ORM\JoinColumn(name="type_id", referencedColumnName="id")
+     * @Selectable()
      */
     protected $attachement_type;
 
diff --git a/src/Entity/Base/StructuralDBElement.php b/src/Entity/Base/StructuralDBElement.php
index 1ce888bc..db749f7e 100644
--- a/src/Entity/Base/StructuralDBElement.php
+++ b/src/Entity/Base/StructuralDBElement.php
@@ -275,6 +275,14 @@ abstract class StructuralDBElement extends AttachmentContainingDBElement
         return $this->children;
     }
 
+    /**
+     * @return bool
+     */
+    public function isNotSelectable(): bool
+    {
+        return $this->not_selectable;
+    }
+
     /******************************************************************************
      *
      * Setters
@@ -317,6 +325,16 @@ abstract class StructuralDBElement extends AttachmentContainingDBElement
         return $this;
     }
 
+    /**
+     * @param bool $not_selectable
+     * @return StructuralDBElement
+     */
+    public function setNotSelectable(bool $not_selectable): StructuralDBElement
+    {
+        $this->not_selectable = $not_selectable;
+        return $this;
+    }
+
     public function clearChildren() : self
     {
         $this->children = new ArrayCollection();
diff --git a/src/Entity/Parts/Part.php b/src/Entity/Parts/Part.php
index 379808c3..7e14ef60 100644
--- a/src/Entity/Parts/Part.php
+++ b/src/Entity/Parts/Part.php
@@ -66,6 +66,7 @@ use App\Entity\Attachments\AttachmentContainingDBElement;
 use App\Entity\Devices\Device;
 use App\Entity\PriceInformations\Orderdetail;
 use App\Security\Annotations\ColumnSecurity;
+use App\Validator\Constraints\Selectable;
 use Doctrine\ORM\Mapping as ORM;
 
 use Symfony\Component\Validator\Constraints as Assert;
@@ -89,6 +90,7 @@ class Part extends AttachmentContainingDBElement
      * @var Category
      * @ORM\ManyToOne(targetEntity="Category", inversedBy="parts")
      * @ORM\JoinColumn(name="id_category", referencedColumnName="id")
+     * @Selectable()
      */
     protected $category;
 
@@ -98,6 +100,7 @@ class Part extends AttachmentContainingDBElement
      * @ORM\JoinColumn(name="id_footprint", referencedColumnName="id")
      *
      * @ColumnSecurity(prefix="footprint", type="object")
+     * @Selectable()
      */
     protected $footprint;
 
@@ -107,6 +110,7 @@ class Part extends AttachmentContainingDBElement
      * @ORM\JoinColumn(name="id_manufacturer", referencedColumnName="id")
      *
      * @ColumnSecurity(prefix="manufacturer", type="object")
+     * @Selectable()
      */
     protected $manufacturer;
 
diff --git a/src/Entity/Parts/PartLot.php b/src/Entity/Parts/PartLot.php
index 7c974c87..83626d79 100644
--- a/src/Entity/Parts/PartLot.php
+++ b/src/Entity/Parts/PartLot.php
@@ -35,6 +35,7 @@ namespace App\Entity\Parts;
 use App\Entity\Base\DBElement;
 use App\Entity\Base\NamedDBElement;
 use App\Entity\Base\TimestampTrait;
+use App\Validator\Constraints\Selectable;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Validator\Constraints as Assert;
 
@@ -74,6 +75,7 @@ class PartLot extends DBElement
      * @var Storelocation The storelocation of this lot
      * @ORM\ManyToOne(targetEntity="Storelocation")
      * @ORM\JoinColumn(name="id_store_location", referencedColumnName="id")
+     * @Selectable()
      */
     protected $storage_location;
 
diff --git a/src/Entity/Parts/Supplier.php b/src/Entity/Parts/Supplier.php
index 14a3cf1c..cbd8eefe 100644
--- a/src/Entity/Parts/Supplier.php
+++ b/src/Entity/Parts/Supplier.php
@@ -63,6 +63,7 @@ namespace App\Entity\Parts;
 
 use App\Entity\Base\Company;
 use App\Entity\PriceInformations\Currency;
+use App\Validator\Constraints\Selectable;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Validator\Constraints as Assert;
 
@@ -95,6 +96,7 @@ class Supplier extends Company
      * Set to null, to use global base currency.
      * @ORM\ManyToOne(targetEntity="App\Entity\PriceInformations\Currency")
      * @ORM\JoinColumn(name="default_currency_id", referencedColumnName="id", nullable=true)
+     * @Selectable()
      */
     protected $default_currency;
 
diff --git a/src/Entity/PriceInformations/Pricedetail.php b/src/Entity/PriceInformations/Pricedetail.php
index d2c8e7b2..561617cd 100644
--- a/src/Entity/PriceInformations/Pricedetail.php
+++ b/src/Entity/PriceInformations/Pricedetail.php
@@ -62,6 +62,7 @@ declare(strict_types=1);
 namespace App\Entity\PriceInformations;
 
 use App\Entity\Base\DBElement;
+use App\Validator\Constraints\Selectable;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
 use Symfony\Component\Validator\Constraints as Assert;
@@ -94,6 +95,7 @@ class Pricedetail extends DBElement
      * If this is null, the global base unit is assumed.
      * @ORM\ManyToOne(targetEntity="Currency")
      * @ORM\JoinColumn(name="id_currency", referencedColumnName="id", nullable=true)
+     * @Selectable()
      */
     protected $currency;
 
diff --git a/src/Entity/UserSystem/User.php b/src/Entity/UserSystem/User.php
index 05f38163..d7cbded1 100644
--- a/src/Entity/UserSystem/User.php
+++ b/src/Entity/UserSystem/User.php
@@ -63,6 +63,7 @@ namespace App\Entity\UserSystem;
 
 use App\Entity\Base\NamedDBElement;
 use App\Security\Interfaces\HasPermissionsInterface;
+use App\Validator\Constraints\Selectable;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Validator\Constraints as Assert;
@@ -156,6 +157,7 @@ class User extends NamedDBElement implements UserInterface, HasPermissionsInterf
      * @var Group|null the group this user belongs to
      * @ORM\ManyToOne(targetEntity="Group", inversedBy="users", fetch="EAGER")
      * @ORM\JoinColumn(name="group_id", referencedColumnName="id")
+     * @Selectable()
      */
     protected $group;
 
diff --git a/src/Form/BaseEntityAdminForm.php b/src/Form/BaseEntityAdminForm.php
index 2a81a279..e7dc268a 100644
--- a/src/Form/BaseEntityAdminForm.php
+++ b/src/Form/BaseEntityAdminForm.php
@@ -37,6 +37,7 @@ use App\Entity\Base\StructuralDBElement;
 use FOS\CKEditorBundle\Form\Type\CKEditorType;
 use Symfony\Bridge\Doctrine\Form\Type\EntityType;
 use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\Extension\Core\Type\CheckboxType;
 use Symfony\Component\Form\Extension\Core\Type\ResetType;
 use Symfony\Component\Form\Extension\Core\Type\SubmitType;
 use Symfony\Component\Form\Extension\Core\Type\TextType;
@@ -69,6 +70,10 @@ class BaseEntityAdminForm extends AbstractType
                 'attr' => ['class' => 'selectpicker', 'data-live-search' => true], 'required' => false, 'label' => 'parent.label',
                 'disabled' => !$this->security->isGranted($is_new ? 'create' : 'move', $entity), ])
 
+            ->add('not_selectable', CheckboxType::class, ['required' => false,
+                'label' => 'not_selectable.label', 'help' => 'not_selectable.help', 'label_attr'=> ['class' => 'checkbox-custom'],
+                'disabled' => !$this->security->isGranted($is_new ? 'create' : 'edit', $entity) ])
+
             ->add('comment', CKEditorType::class, ['required' => false,
                 'label' => 'comment.label', 'attr' => ['rows' => 4], 'help' => 'bbcode.hint',
                 'disabled' => !$this->security->isGranted($is_new ? 'create' : 'edit', $entity)]);
diff --git a/src/Validator/Constraints/NoneOfItsChildrenValidator.php b/src/Validator/Constraints/NoneOfItsChildrenValidator.php
index 5340772c..0c09642f 100644
--- a/src/Validator/Constraints/NoneOfItsChildrenValidator.php
+++ b/src/Validator/Constraints/NoneOfItsChildrenValidator.php
@@ -37,6 +37,7 @@ use Symfony\Bundle\MakerBundle\Str;
 use Symfony\Component\Form\Exception\UnexpectedTypeException;
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedValueException;
 
 /**
  * The validator for the NoneOfItsChildren annotation.
@@ -62,6 +63,11 @@ class NoneOfItsChildrenValidator extends ConstraintValidator
             return;
         }
 
+        //Check type of value. Validating only works for StructuralDBElements
+        if (!$value instanceof StructuralDBElement) {
+            throw new UnexpectedValueException($value, 'StructuralDBElement');
+        }
+
         //Check if the object is assigned to itself
         /** @var StructuralDBElement $entity */
         $entity = $this->context->getObject();
diff --git a/src/Validator/Constraints/Selectable.php b/src/Validator/Constraints/Selectable.php
new file mode 100644
index 00000000..701973e7
--- /dev/null
+++ b/src/Validator/Constraints/Selectable.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ *
+ * part-db version 0.1
+ * Copyright (C) 2005 Christoph Lechner
+ * http://www.cl-projects.de/
+ *
+ * part-db version 0.2+
+ * Copyright (C) 2009 K. Jacobs and others (see authors.php)
+ * http://code.google.com/p/part-db/
+ *
+ * Part-DB Version 0.4+
+ * Copyright (C) 2016 - 2019 Jan Böhmer
+ * https://github.com/jbtronics
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ *
+ */
+
+namespace App\Validator\Constraints;
+
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * If a property is marked with this constraint, the choosen value (of type StructuralDBElement)
+ * must NOT be marked as not selectable.
+ *
+ * @package App\Validator\Constraints
+ * @Annotation
+ */
+class Selectable extends Constraint
+{
+    public $message = 'validator.isSelectable';
+}
\ No newline at end of file
diff --git a/src/Validator/Constraints/SelectableValidator.php b/src/Validator/Constraints/SelectableValidator.php
new file mode 100644
index 00000000..f9bdb7c8
--- /dev/null
+++ b/src/Validator/Constraints/SelectableValidator.php
@@ -0,0 +1,78 @@
+<?php
+/**
+ *
+ * part-db version 0.1
+ * Copyright (C) 2005 Christoph Lechner
+ * http://www.cl-projects.de/
+ *
+ * part-db version 0.2+
+ * Copyright (C) 2009 K. Jacobs and others (see authors.php)
+ * http://code.google.com/p/part-db/
+ *
+ * Part-DB Version 0.4+
+ * Copyright (C) 2016 - 2019 Jan Böhmer
+ * https://github.com/jbtronics
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ *
+ */
+
+namespace App\Validator\Constraints;
+
+use App\Entity\Base\StructuralDBElement;
+use Symfony\Component\Form\Exception\UnexpectedTypeException;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedValueException;
+
+/**
+ * The validator for the Selectable constraint.
+ * @package App\Validator\Constraints
+ */
+class SelectableValidator extends ConstraintValidator
+{
+
+    /**
+     * Checks if the passed value is valid.
+     *
+     * @param mixed $value The value that should be validated
+     * @param \Symfony\Component\Validator\Constraint $constraint The constraint for the validation
+     */
+    public function validate($value, Constraint $constraint)
+    {
+        if (!$constraint instanceof Selectable) {
+            throw new UnexpectedTypeException($constraint, Selectable::class);
+        }
+
+        // custom constraints should ignore null and empty values to allow
+        // other constraints (NotBlank, NotNull, etc.) take care of that
+        if (null === $value || '' === $value) {
+            return;
+        }
+
+        //Check type of value. Validating only works for StructuralDBElements
+        if (!$value instanceof StructuralDBElement) {
+            throw new UnexpectedValueException($value, 'StructuralDBElement');
+        }
+
+        //Check if the value is not selectable -> show error message then.
+        if ($value->isNotSelectable()) {
+            $this->context->buildViolation($constraint->message)
+                ->setParameter('{{ name }}', $value->getName())
+                ->setParameter('{{ full_path }}', $value->getFullPath())
+                ->addViolation();
+        }
+    }
+}
\ No newline at end of file
diff --git a/templates/AdminPages/EntityAdminBase.html.twig b/templates/AdminPages/EntityAdminBase.html.twig
index ea71b3ae..7f971e72 100644
--- a/templates/AdminPages/EntityAdminBase.html.twig
+++ b/templates/AdminPages/EntityAdminBase.html.twig
@@ -68,6 +68,7 @@
                                 {% if form.parent%}
                                     {{ form_row(form.parent) }}
                                 {% endif %}
+                                {{ form_row(form.not_selectable) }}
 
                                 {% block additional_controls %}{% endblock %}