diff --git a/lib/core/viewer/components/viewer.component.html b/lib/core/viewer/components/viewer.component.html
index 12f1af3ed3..0058365c91 100644
--- a/lib/core/viewer/components/viewer.component.html
+++ b/lib/core/viewer/components/viewer.component.html
@@ -133,7 +133,7 @@
                         </ng-container>
 
                         <ng-container *ngSwitchCase="'custom'">
-                            <span *ngFor="let extensionTemplate of extensionTemplates">
+                            <span class="adf-viewer-custom-content" *ngFor="let extensionTemplate of extensionTemplates">
                                 <ng-template *ngIf="extensionTemplate.isVisible" [ngTemplateOutlet]="extensionTemplate.template" [ngTemplateOutletContext]="{ urlFileContent: urlFileContent, extension:extension }">
                                 </ng-template>
                             </span>
diff --git a/lib/core/viewer/components/viewer.component.scss b/lib/core/viewer/components/viewer.component.scss
index 600ed97138..5bb15060cb 100644
--- a/lib/core/viewer/components/viewer.component.scss
+++ b/lib/core/viewer/components/viewer.component.scss
@@ -70,6 +70,10 @@
             justify-content: center;
         }
 
+        &-custom-content {
+            width: 100vw;
+        }
+
         &-unknown-content {
             align-items: center;
             display: flex;