     }
 
     private lazy var compareToolbarButton = UIBarButtonItem(title: CommonStrings.compareTitle, style: .plain, target: self, action: #selector(showDiff(_:)))
-    private lazy var firstComparisonSelectionButton = makeComparisonSelectionButton()
-    private lazy var secondComparisonSelectionButton = makeComparisonSelectionButton()
+    private lazy var firstComparisonSelectionButton: AlignedImageButton = {
+        let button = makeComparisonSelectionButton()
+        button.tag = 0
+        return button
+    }()
+    private lazy var secondComparisonSelectionButton: AlignedImageButton = {
+        let button = makeComparisonSelectionButton()
+        button.tag = 1
+        return button
+    }()
     private var comparisonSelectionButtonWidthConstraints = [NSLayoutConstraint]()
 
     private func makeComparisonSelectionButton() -> AlignedImageButton {


    var openSelectionIndex = 0
    private var postedMaxRevisionsSelectedAccessibilityNotification = false
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        selectedCellsCount += 1
        defer {

            button.imageView?.tintColor = themeModel.authorColor
            button.setTitleColor(themeModel.authorColor, for: .normal)
            button.tintColor = themeModel.authorColor
            indexPathsSelectedForComparison[button.tag] = indexPath
        }
        updateSelectionIndex(openSelectionIndex, for: cell, at: indexPath)
        updateSelectionThemeModel(themeModel, for: cell, at: indexPath)
        cell.apply(theme: theme)

        openSelectionIndex += 1
    }

    @objc private func scrollToComparisonSelection(_ sender: UIButton) {
        guard let indexPath = indexPathsSelectedForComparison[sender.tag] else {
            return
        }
        collectionView.scrollToItem(at: indexPath, at: .centeredVertically, animated: true)
    }

    func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
