diff --git a/backend/pkg/http/middleware/auth.go b/backend/pkg/http/middleware/auth.go
index 41146aca5..4ffc6e242 100644
--- a/backend/pkg/http/middleware/auth.go
+++ b/backend/pkg/http/middleware/auth.go
@@ -41,7 +41,13 @@ func setActor(c *gin.Context, a Actor, supportOf SupportOfFunc) bool {
 
 	c.Set("support_access", a.Support)
 
-	ctx := authz.WithTenantID(c.Request.Context(), a.TenantID)
+	tid := a.TenantID
+	if tid == "" && !a.Internal {
+		// platform admin with no tenant selected → scope to the default
+		// tenant instead of "" (which downstream usecases fail-open on).
+		tid = authz.DefaultTenantID
+	}
+	ctx := authz.WithTenantID(c.Request.Context(), tid)
 
 	if a.Internal && a.TenantID == "" {
 		ctx = tenancy.WithAllTenantsRead(ctx)
diff --git a/frontend/src/features/platform-broadcast/components/PlatformBroadcastButton.tsx b/frontend/src/features/platform-broadcast/components/PlatformBroadcastButton.tsx
index 00e110ce8..09d5f3221 100644
--- a/frontend/src/features/platform-broadcast/components/PlatformBroadcastButton.tsx
+++ b/frontend/src/features/platform-broadcast/components/PlatformBroadcastButton.tsx
@@ -1,6 +1,7 @@
 import { useState, type ReactNode } from 'react'
 import { Radio } from 'lucide-react'
 import { Button } from '@/shared/components/ui/button'
+import { Tooltip, TooltipContent, TooltipTrigger } from '@/shared/components/ui/tooltip'
 import { useAuth } from '@/features/auth/services/auth.context'
 import { useBilling } from '@/features/billing'
 import { useSupportTenant } from '@/shared/lib/current-tenant'
@@ -48,15 +49,21 @@ export function PlatformBroadcastButton(props: PlatformBroadcastButtonProps) {
 
   return (
     <>
-      <Button
-        variant={props.variant ?? 'outline'}
-        size={props.size ?? 'sm'}
-        disabled={props.disabled}
-        onClick={() => setOpen(true)}
-      >
-        <Radio size={14} className="mr-1.5" />
-        {props.label}
-      </Button>
+      <Tooltip>
+        <TooltipTrigger asChild>
+          <Button
+            variant={props.variant ?? 'outline'}
+            size="icon"
+            disabled={props.disabled}
+            onClick={() => setOpen(true)}
+            aria-label={props.label}
+            className={props.size === 'sm' ? 'h-8 w-8' : undefined}
+          >
+            <Radio size={14} />
+          </Button>
+        </TooltipTrigger>
+        <TooltipContent>{props.label}</TooltipContent>
+      </Tooltip>
       <BroadcastDialog
         open={open}
         title={props.title}
diff --git a/frontend/src/shared/i18n/locales/de.json b/frontend/src/shared/i18n/locales/de.json
index 0dfc7bdb3..c261f2957 100644
--- a/frontend/src/shared/i18n/locales/de.json
+++ b/frontend/src/shared/i18n/locales/de.json
@@ -5552,7 +5552,7 @@
     "leave": "Verlassen"
   },
   "platformBroadcast": {
-    "button": "Auf Mandanten anwenden…",
+    "button": "Auf alle Mandanten anwenden",
     "action": {
       "create": "{{resource}} verteilt erstellen",
       "update": "{{resource}} verteilt aktualisieren",
diff --git a/frontend/src/shared/i18n/locales/en.json b/frontend/src/shared/i18n/locales/en.json
index 6b834b518..0d0080a8f 100644
--- a/frontend/src/shared/i18n/locales/en.json
+++ b/frontend/src/shared/i18n/locales/en.json
@@ -5537,7 +5537,7 @@
     "leave": "Leave"
   },
   "platformBroadcast": {
-    "button": "Apply to tenants…",
+    "button": "Apply to all tenants",
     "action": {
       "create": "Broadcast {{resource}} create",
       "update": "Broadcast {{resource}} update",
diff --git a/frontend/src/shared/i18n/locales/es.json b/frontend/src/shared/i18n/locales/es.json
index fe28d59b2..56f684205 100644
--- a/frontend/src/shared/i18n/locales/es.json
+++ b/frontend/src/shared/i18n/locales/es.json
@@ -5514,7 +5514,7 @@
     "leave": "Salir"
   },
   "platformBroadcast": {
-    "button": "Aplicar a inquilinos…",
+    "button": "Aplicar a todos los inquilinos",
     "action": {
       "create": "Difundir creación de {{resource}}",
       "update": "Difundir actualización de {{resource}}",
diff --git a/frontend/src/shared/i18n/locales/fr.json b/frontend/src/shared/i18n/locales/fr.json
index 44c956ec9..9b1fbc506 100644
--- a/frontend/src/shared/i18n/locales/fr.json
+++ b/frontend/src/shared/i18n/locales/fr.json
@@ -5552,7 +5552,7 @@
     "leave": "Quitter"
   },
   "platformBroadcast": {
-    "button": "Appliquer aux locataires…",
+    "button": "Appliquer à tous les locataires",
     "action": {
       "create": "Diffuser la création de {{resource}}",
       "update": "Diffuser la mise à jour de {{resource}}",
diff --git a/frontend/src/shared/i18n/locales/it.json b/frontend/src/shared/i18n/locales/it.json
index 8e09f1d63..81c8b5245 100644
--- a/frontend/src/shared/i18n/locales/it.json
+++ b/frontend/src/shared/i18n/locales/it.json
@@ -5552,7 +5552,7 @@
     "leave": "Esci"
   },
   "platformBroadcast": {
-    "button": "Applica ai tenant…",
+    "button": "Applica a tutti i tenant",
     "action": {
       "create": "Trasmetti creazione {{resource}}",
       "update": "Trasmetti aggiornamento {{resource}}",
diff --git a/frontend/src/shared/i18n/locales/pt.json b/frontend/src/shared/i18n/locales/pt.json
index a82564128..bb569677c 100644
--- a/frontend/src/shared/i18n/locales/pt.json
+++ b/frontend/src/shared/i18n/locales/pt.json
@@ -5514,7 +5514,7 @@
     "leave": "Sair"
   },
   "platformBroadcast": {
-    "button": "Aplicar aos inquilinos…",
+    "button": "Aplicar a todos os inquilinos",
     "action": {
       "create": "Transmitir criação de {{resource}}",
       "update": "Transmitir atualização de {{resource}}",
diff --git a/frontend/src/shared/i18n/locales/ru.json b/frontend/src/shared/i18n/locales/ru.json
index e86cc8ff3..18eb782ff 100644
--- a/frontend/src/shared/i18n/locales/ru.json
+++ b/frontend/src/shared/i18n/locales/ru.json
@@ -5576,7 +5576,7 @@
     "leave": "Выйти"
   },
   "platformBroadcast": {
-    "button": "Применить к арендаторам…",
+    "button": "Применить ко всем арендаторам",
     "action": {
       "create": "Массовое создание: {{resource}}",
       "update": "Массовое обновление: {{resource}}",