ViewPhotoAlbum: don't populate filter box if there are no album contributors

templates/AlbumButtonBox.php

@@ -28,26 +28,31 @@ class AlbumButtonBox extends Template
 			echo '
 				<a class="btn btn-light" href="', $button['url'], '">', $button['caption'], '</a>';
 
-		echo '
+		if (!empty($this->filters))
+		{
+			echo '
 				<div class="dropdown">
 					<button class="btn btn-light dropdown-toggle" type="button" data-bs-toggle="dropdown" aria-expanded="false">
 						<i class="bi bi-filter"></i>
 					</button>
 					<ul class="dropdown-menu">';
 
-		foreach ($this->filters as $key => $filter)
-		{
-			$is_active = $key === $this->active_filter;
-			echo '
+			foreach ($this->filters as $key => $filter)
+			{
+				$is_active = $key === $this->active_filter;
+				echo '
 						<li><a class="dropdown-item', $is_active ? ' active' : '',
 							'" href="', $filter['link'], '">',
 							$filter['caption'],
 							'</a></li>';
+			}
+
+			echo '
+					</ul>
+				</div>';
 		}
 
 		echo '
-					</ul>
-				</div>
 			</div>';
 	}
 }