diff --git a/src/activities/Elsa.Activities.Email/Activities/SendEmail/SendEmail.cs b/src/activities/Elsa.Activities.Email/Activities/SendEmail/SendEmail.cs
index 80dea68dd..2acf8cb8e 100644
--- a/src/activities/Elsa.Activities.Email/Activities/SendEmail/SendEmail.cs
+++ b/src/activities/Elsa.Activities.Email/Activities/SendEmail/SendEmail.cs
@@ -30,13 +30,13 @@ namespace Elsa.Activities.Email
         [ActivityProperty(Hint = "The sender's email address.")]
         public string? From { get; set; }
 
-        [ActivityProperty(Hint = "The recipients email addresses.")]
+        [ActivityProperty(Hint = "The recipients email addresses.", UIHint = ActivityPropertyUIHints.MultiText)]
         public ICollection<string> To { get; set; } = new List<string>();
 
-        [ActivityProperty(Hint = "The cc recipients email addresses. (Optional)")]
+        [ActivityProperty(Hint = "The cc recipients email addresses. (Optional)", UIHint = ActivityPropertyUIHints.MultiText)]
         public ICollection<string> Cc { get; set; } = new List<string>();
 
-        [ActivityProperty(Hint = "The Bcc recipients email addresses. (Optional)")]
+        [ActivityProperty(Hint = "The Bcc recipients email addresses. (Optional)", UIHint = ActivityPropertyUIHints.MultiText)]
         public ICollection<string> Bcc { get; set; } = new List<string>();
 
         [ActivityProperty(Hint = "The subject of the email message.")]
@@ -48,7 +48,7 @@ namespace Elsa.Activities.Email
         protected override async ValueTask<IActivityExecutionResult> OnExecuteAsync(ActivityExecutionContext context)
         {
             var message = new MimeMessage();
-            var from = From is null or "" ? _options.DefaultSender : From; 
+            var from = From is null or "" ? _options.DefaultSender : From;
 
             message.From.Add(MailboxAddress.Parse(from));
             message.Subject = Subject;
@@ -61,7 +61,7 @@ namespace Elsa.Activities.Email
             SetRecipientsEmailAddresses(message.To, To);
             SetRecipientsEmailAddresses(message.Cc, Cc);
             SetRecipientsEmailAddresses(message.Bcc, Bcc);
-           
+
             await _smtpService.SendAsync(message, context.CancellationToken);
 
             return Done();
diff --git a/src/core/Elsa.Abstractions/Models/ActivityDefinitionProperty.cs b/src/core/Elsa.Abstractions/Models/ActivityDefinitionProperty.cs
index 1658b8f7a..a18546c6b 100644
--- a/src/core/Elsa.Abstractions/Models/ActivityDefinitionProperty.cs
+++ b/src/core/Elsa.Abstractions/Models/ActivityDefinitionProperty.cs
@@ -18,7 +18,7 @@
         }
 
         public string Name { get; set; } = default!;
-        public string Syntax { get; set; } = default!;
-        public string Expression { get; set; } = default!;
+        public string? Syntax { get; set; }
+        public string? Expression { get; set; }
     }
 }
\ No newline at end of file
diff --git a/src/designer/elsa-workflows-studio/src/components/editors/properties/elsa-dropdown-property/elsa-dropdown-property.tsx b/src/designer/elsa-workflows-studio/src/components/editors/properties/elsa-dropdown-property/elsa-dropdown-property.tsx
index 5504eeb98..f153fd00a 100644
--- a/src/designer/elsa-workflows-studio/src/components/editors/properties/elsa-dropdown-property/elsa-dropdown-property.tsx
+++ b/src/designer/elsa-workflows-studio/src/components/editors/properties/elsa-dropdown-property/elsa-dropdown-property.tsx
@@ -28,7 +28,7 @@ export class ElsaDropdownProperty {
     const fieldName = propertyName;
     const fieldLabel = propertyDescriptor.label || propertyName;
     const fieldHint = propertyDescriptor.hint;
-    const options = propertyDescriptor.options as Array<any>;
+    const options = propertyDescriptor.options as Array<any> || [];
     const value = this.currentValue;
 
     return (