Make the All Unread feed eligible for the Clean Up command. Issue #2417

Mac/MainWindow/Timeline/TimelineViewController.swift

@@ -44,11 +44,20 @@ final class TimelineViewController: NSViewController, UndoableCommandRunner, Unr
 	}
 	
 	var isCleanUpAvailable: Bool {
-		guard isReadFiltered ?? false else { return false }
+		let isEligibleForCleanUp: Bool?
+		
+		if representedObjects?.count == 1, let timelineFeed = representedObjects?.first as? Feed, timelineFeed.defaultReadFilterType == .alwaysRead {
+			isEligibleForCleanUp = true
+		} else {
+			isEligibleForCleanUp = isReadFiltered
+		}
+
+		guard isEligibleForCleanUp ?? false else { return false }
 		
 		let readSelectedCount = selectedArticles.filter({ $0.status.read }).count
 		let readArticleCount = articles.count - unreadCount
 		let availableToCleanCount = readArticleCount - readSelectedCount
+		
 		return availableToCleanCount > 0
 	}