diff --git a/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpOptionsForm.js b/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpOptionsForm.js
index e27ca5fa5b..987e8e09c0 100644
--- a/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpOptionsForm.js
+++ b/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpOptionsForm.js
@@ -2,7 +2,6 @@ import PropTypes from 'prop-types';
 import React, {useContext} from 'react';
 import {FormattedMessage} from 'react-intl';
 
-import {FormContext} from 'components/admin/form_design/Context';
 import Fieldset from 'components/admin/forms/Fieldset';
 import ModalOptionsConfiguration from 'components/admin/forms/ModalOptionsConfiguration';
 import {
@@ -12,23 +11,12 @@ import {
 } from 'components/admin/forms/ValidationErrors';
 import {getChoicesFromSchema} from 'utils/json-schema';
 
-import {FormVariablesSelect, Path, ServiceSelect} from './fields';
+import {Path, ServiceSelect, Variables} from './fields';
 
 const JSONDumpOptionsForm = ({name, label, schema, formData, onChange}) => {
   const validationErrors = useContext(ValidationErrorContext);
   const relevantErrors = filterErrors(name, validationErrors);
 
-  // Get form variables and create form variable options
-  const formContext = useContext(FormContext);
-  const formVariables = formContext.formVariables ?? [];
-  const staticVariables = formContext.staticVariables ?? [];
-  const allVariables = staticVariables.concat(formVariables);
-
-  const variableOptions = [];
-  for (const variable of allVariables) {
-    variableOptions.push({value: variable.key, label: variable.name});
-  }
-
   // Create service options
   const {service} = schema.properties;
   const serviceOptions = getChoicesFromSchema(service.enum, service.enumNames).map(
@@ -53,13 +41,13 @@ const JSONDumpOptionsForm = ({name, label, schema, formData, onChange}) => {
         ...formData,
       }}
       onSubmit={values => onChange({formData: values})}
-      modalSize="medium"
+      modalSize="large"
     >
       <ValidationErrorsProvider errors={relevantErrors}>
         <Fieldset>
           <ServiceSelect options={serviceOptions} />
           <Path />
-          <FormVariablesSelect options={variableOptions} />
+          <Variables />
         </Fieldset>
       </ValidationErrorsProvider>
     </ModalOptionsConfiguration>
diff --git a/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpVariableConfigurationEditor.js b/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpVariableConfigurationEditor.js
index 31bb9b8fea..75f5b4077c 100644
--- a/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpVariableConfigurationEditor.js
+++ b/src/openforms/js/components/admin/form_design/registrations/json_dump/JSONDumpVariableConfigurationEditor.js
@@ -37,7 +37,7 @@ const JSONDumpVariableConfigurationEditor = ({variable}) => {
             const newVariables = shouldBeIncluded
               ? [...variables, variable.key] // add the variable to the array
               : variables.filter(key => key !== variable.key); // remove the variable from the array
-            setFieldValue('variables', variables);
+            setFieldValue('variables', newVariables);
           }}
         />
       </Field>
diff --git a/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/FormVariablesSelect.js b/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/FormVariablesSelect.js
deleted file mode 100644
index 7ac5993b2b..0000000000
--- a/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/FormVariablesSelect.js
+++ /dev/null
@@ -1,66 +0,0 @@
-import {useField} from 'formik';
-import PropTypes from 'prop-types';
-import React from 'react';
-import {FormattedMessage} from 'react-intl';
-
-import Field from 'components/admin/forms/Field';
-import FormRow from 'components/admin/forms/FormRow';
-import ReactSelect from 'components/admin/forms/ReactSelect';
-
-const FormVariablesSelect = ({options}) => {
-  const [fieldProps, , {setValue}] = useField('variables');
-
-  const values = [];
-  if (fieldProps.value && fieldProps.value.length) {
-    fieldProps.value.forEach(item => {
-      const selectedOption = options.find(option => option.value === item);
-      if (selectedOption) {
-        values.push(selectedOption);
-      }
-    });
-  }
-
-  return (
-    <FormRow>
-      <Field
-        name="variables"
-        label={
-          <FormattedMessage
-            description="JSON registration options 'variables' label"
-            defaultMessage="Variables"
-          />
-        }
-        helpText={
-          <FormattedMessage
-            description="JSON registration options 'variables' helpText"
-            defaultMessage="Which variables to include in the data to be sent"
-          />
-        }
-        required
-        noManageChildProps
-      >
-        <ReactSelect
-          name="variables"
-          options={options}
-          isMulti
-          required
-          value={values}
-          onChange={newValue => {
-            setValue(newValue.map(item => item.value));
-          }}
-        />
-      </Field>
-    </FormRow>
-  );
-};
-
-FormVariablesSelect.propTypes = {
-  options: PropTypes.arrayOf(
-    PropTypes.shape({
-      value: PropTypes.string.isRequired,
-      label: PropTypes.node.isRequired,
-    })
-  ).isRequired,
-};
-
-export default FormVariablesSelect;
diff --git a/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/Variables.js b/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/Variables.js
new file mode 100644
index 0000000000..2d934a3ced
--- /dev/null
+++ b/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/Variables.js
@@ -0,0 +1,43 @@
+import {useField} from 'formik';
+import React from 'react';
+import {FormattedMessage} from 'react-intl';
+
+import Field from 'components/admin/forms/Field';
+import FormRow from 'components/admin/forms/FormRow';
+import VariableSelection from 'components/admin/forms/VariableSelection';
+
+const Variables = () => {
+  const [fieldProps] = useField('variables');
+
+  return (
+    <FormRow>
+      <Field
+        name="variables"
+        label={
+          <FormattedMessage
+            description="JSON registration options 'variables' label"
+            defaultMessage="Variables"
+          />
+        }
+        helpText={
+          <FormattedMessage
+            description="JSON registration options 'variables' helpText"
+            defaultMessage="Which variables to include in the data to be sent"
+          />
+        }
+        required
+        noManageChildProps
+      >
+        <VariableSelection
+          {...fieldProps}
+          isMulti
+          required
+          closeMenuOnSelect={false}
+          includeStaticVariables={true}
+        />
+      </Field>
+    </FormRow>
+  );
+};
+
+export default Variables;
diff --git a/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/index.js b/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/index.js
index 2b2cab17e5..ab0ba696a9 100644
--- a/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/index.js
+++ b/src/openforms/js/components/admin/form_design/registrations/json_dump/fields/index.js
@@ -1,5 +1,5 @@
-import FormVariablesSelect from './FormVariablesSelect';
 import Path from './Path';
 import ServiceSelect from './ServiceSelect';
+import Variables from './Variables';
 
-export {FormVariablesSelect, Path, ServiceSelect};
+export {Path, ServiceSelect, Variables};