             cell.author = item.user
             cell.sizeDiff = item.revisionSize
             cell.comment = item.parsedComment?.removingHTML
-            if !cell.isSelected {
+            if isSelected, let selectionIndex = indexPathsSelectedForComparisonGroupedByButtonTags.first(where: { $0.value == indexPath })?.key {
+                cell.isSelected = true
+                collectionView.selectItem(at: indexPath, animated: false, scrollPosition: [])
+                cell.selectionThemeModel = selectionIndex == 0 ? firstSelectionThemeModel : secondSelectionThemeModel
+                cell.selectionIndex = selectionIndex
+            } else {
                 cell.selectionThemeModel = maxNumberOfRevisionsSelected ? disabledSelectionThemeModel : nil
             }
         }

    private func configure(cell: PageHistoryCollectionViewCell, for item: WMFPageHistoryRevision? = nil, at indexPath: IndexPath) {
        let item = item ?? pageHistorySections[indexPath.section].items[indexPath.item]
        let revisionID = NSNumber(value: item.revisionID)
        defer {
            cell.setEditing(state == .editing, animated: false)
            cell.enableEditing(!maxNumberOfRevisionsSelected, animated: false)
            cell.apply(theme: theme)
        }
        if let cachedCellContent = cellContentCache.object(forKey: revisionID) {

                    cell.isSelected = true
                    collectionView.selectItem(at: indexPath, animated: false, scrollPosition: [])
                }
                if isSelected {
                    cell.selectionThemeModel = cachedCellContent.selectionThemeModel
                } else {
                    cell.selectionThemeModel = maxNumberOfRevisionsSelected ? disabledSelectionThemeModel : nil
