diff --git a/assets/js/src/form_editor/blocks/custom_textarea/edit.jsx b/assets/js/src/form_editor/blocks/custom_textarea/edit.jsx
index 43e33f4449..9aa150974b 100644
--- a/assets/js/src/form_editor/blocks/custom_textarea/edit.jsx
+++ b/assets/js/src/form_editor/blocks/custom_textarea/edit.jsx
@@ -113,7 +113,7 @@ const CustomTextAreaEdit = ({ attributes, setAttributes, clientId }) => {
 
   const inputStyles = !attributes.styles.inheritFromTheme ? {
     borderRadius: attributes.styles.borderRadius ? `${attributes.styles.borderRadius}px` : 0,
-    borderWidth: attributes.styles.borderSize ? `${attributes.styles.borderSize}px` : '1px',
+    borderWidth: attributes.styles.borderSize !== undefined ? `${attributes.styles.borderSize}px` : '1px',
     borderColor: attributes.styles.borderColor || 'initial',
   } : {};
 
diff --git a/assets/js/src/form_editor/blocks/submit/edit.jsx b/assets/js/src/form_editor/blocks/submit/edit.jsx
index c5a1fabada..a83ddf1738 100644
--- a/assets/js/src/form_editor/blocks/submit/edit.jsx
+++ b/assets/js/src/form_editor/blocks/submit/edit.jsx
@@ -32,7 +32,7 @@ const SubmitEdit = ({ attributes, setAttributes }) => {
   const styles = !attributes.styles.inheritFromTheme ? {
     fontWeight: attributes.styles.bold ? 'bold' : 'inherit',
     borderRadius: attributes.styles.borderRadius ? `${attributes.styles.borderRadius}px` : 0,
-    borderWidth: attributes.styles.borderSize ? `${attributes.styles.borderSize}px` : '1px',
+    borderWidth: attributes.styles.borderSize !== undefined ? `${attributes.styles.borderSize}px` : '1px',
     borderColor: attributes.styles.borderColor || 'initial',
     fontSize: attributes.styles.fontSize ? `${attributes.styles.fontSize}px` : 'inherit',
     color: attributes.styles.fontColor || 'inherit',
diff --git a/assets/js/src/form_editor/blocks/submit/styles_settings.tsx b/assets/js/src/form_editor/blocks/submit/styles_settings.tsx
index 66b59505f2..7ab69152b9 100644
--- a/assets/js/src/form_editor/blocks/submit/styles_settings.tsx
+++ b/assets/js/src/form_editor/blocks/submit/styles_settings.tsx
@@ -82,7 +82,7 @@ const StylesSettings = ({
               />
               <RangeControl
                 label={MailPoet.I18n.t('formSettingsBorderSize')}
-                value={localStyles.borderSize || 1}
+                value={localStyles.borderSize !== undefined ? localStyles.borderSize : 1}
                 min={0}
                 max={10}
                 allowReset
@@ -91,7 +91,7 @@ const StylesSettings = ({
               />
               <RangeControl
                 label={MailPoet.I18n.t('formSettingsBorderRadius')}
-                value={localStyles.borderRadius || 1}
+                value={localStyles.borderRadius !== undefined ? localStyles.borderRadius : 1}
                 min={0}
                 max={40}
                 allowReset
diff --git a/assets/js/src/form_editor/blocks/text_input_edit.jsx b/assets/js/src/form_editor/blocks/text_input_edit.jsx
index 163910c00e..dff623742e 100644
--- a/assets/js/src/form_editor/blocks/text_input_edit.jsx
+++ b/assets/js/src/form_editor/blocks/text_input_edit.jsx
@@ -21,7 +21,7 @@ const TextInputEdit = ({
 
   const inputStyles = !styles.inheritFromTheme ? {
     borderRadius: styles.borderRadius ? `${styles.borderRadius}px` : 0,
-    borderWidth: styles.borderSize ? `${styles.borderSize}px` : '1px',
+    borderWidth: styles.borderSize !== undefined ? `${styles.borderSize}px` : '1px',
     borderColor: styles.borderColor || 'initial',
   } : {};