diff --git a/packages/volto-slate/news/5779.bugfix b/packages/volto-slate/news/5779.bugfix
new file mode 100644
index 0000000000..5c1f633b25
--- /dev/null
+++ b/packages/volto-slate/news/5779.bugfix
@@ -0,0 +1 @@
+Fix sidebar form update. @robgietema
\ No newline at end of file
diff --git a/packages/volto-slate/src/blocks/Table/TableBlockEdit.jsx b/packages/volto-slate/src/blocks/Table/TableBlockEdit.jsx
index 478ba15be9..397bff13fd 100644
--- a/packages/volto-slate/src/blocks/Table/TableBlockEdit.jsx
+++ b/packages/volto-slate/src/blocks/Table/TableBlockEdit.jsx
@@ -5,7 +5,7 @@
 
 import React, { Component } from 'react';
 import PropTypes from 'prop-types';
-import { map, remove } from 'lodash';
+import { isEmpty, map, remove } from 'lodash';
 import { Button, Table } from 'semantic-ui-react';
 import cx from 'classnames';
 import { defineMessages, injectIntl } from 'react-intl';
@@ -227,7 +227,7 @@ class Edit extends Component {
    * @returns {undefined}
    */
   componentDidMount() {
-    if (!this.props.data.table) {
+    if (!this.props.data.table || isEmpty(this.props.data.table)) {
       this.props.onChangeBlock(this.props.block, {
         ...this.props.data,
         table: initialTable,
@@ -243,7 +243,7 @@ class Edit extends Component {
    * @returns {undefined}
    */
   UNSAFE_componentWillReceiveProps(nextProps) {
-    if (!nextProps.data.table) {
+    if (!nextProps.data.table || isEmpty(nextProps.data.table)) {
       this.props.onChangeBlock(nextProps.block, {
         ...nextProps.data,
         table: initialTable,
@@ -528,10 +528,7 @@ class Edit extends Component {
                 icon
                 basic
                 onClick={this.onDeleteRow}
-                disabled={
-                  this.props.data.table &&
-                  this.props.data.table.rows.length === 1
-                }
+                disabled={this.props.data.table?.rows?.length === 1}
                 title={this.props.intl.formatMessage(messages.deleteRow)}
                 aria-label={this.props.intl.formatMessage(messages.deleteRow)}
               >
@@ -569,10 +566,7 @@ class Edit extends Component {
                 icon
                 basic
                 onClick={this.onDeleteCol}
-                disabled={
-                  this.props.data.table &&
-                  this.props.data.table.rows[0].cells.length === 1
-                }
+                disabled={this.props.data.table?.rows?.[0].cells.length === 1}
                 title={this.props.intl.formatMessage(messages.deleteCol)}
                 aria-label={this.props.intl.formatMessage(messages.deleteCol)}
               >
diff --git a/packages/volto/news/5779.bugfix b/packages/volto/news/5779.bugfix
new file mode 100644
index 0000000000..5c1f633b25
--- /dev/null
+++ b/packages/volto/news/5779.bugfix
@@ -0,0 +1 @@
+Fix sidebar form update. @robgietema
\ No newline at end of file
diff --git a/src/components/manage/Form/Form.jsx b/src/components/manage/Form/Form.jsx
index 7b635139ef..af6d1ceaca 100644
--- a/src/components/manage/Form/Form.jsx
+++ b/src/components/manage/Form/Form.jsx
@@ -260,7 +260,7 @@ class Form extends Component {
     }
     if (
       this.props.global &&
-      !isEqual(this.props.globalData, this.state.formData)
+      !isEqual(this.props.globalData, prevProps.globalData)
     ) {
       this.setState({
         formData: this.props.globalData,