diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/IconedTwoLineListItem.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/IconedTwoLineListItem.java
index 9409658ba..3687dfea7 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/IconedTwoLineListItem.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/IconedTwoLineListItem.java
@@ -10,6 +10,7 @@ import javafx.beans.property.StringProperty;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
 import javafx.geometry.Pos;
+import javafx.scene.control.Label;
 import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
 import javafx.scene.layout.HBox;
@@ -21,7 +22,7 @@ import org.jackhuang.hmcl.util.StringUtils;
 
 public class IconedTwoLineListItem extends HBox {
     private final StringProperty title = new SimpleStringProperty(this, "title");
-    private final ObservableList<String> tags = FXCollections.observableArrayList();
+    private final ObservableList<Label> tags = FXCollections.observableArrayList();
     private final StringProperty subtitle = new SimpleStringProperty(this, "subtitle");
     private final StringProperty externalLink = new SimpleStringProperty(this, "externalLink");
     private final ObjectProperty<Image> image = new SimpleObjectProperty<>(this, "image");
@@ -62,7 +63,7 @@ public class IconedTwoLineListItem extends HBox {
         this.title.set(title);
     }
 
-    public ObservableList<String> getTags() {
+    public ObservableList<Label> getTags() {
         return tags;
     }
 
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/TwoLineListItem.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/TwoLineListItem.java
index 51c98e159..b18131fd7 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/TwoLineListItem.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/construct/TwoLineListItem.java
@@ -29,16 +29,22 @@ import javafx.scene.layout.HBox;
 import javafx.scene.layout.VBox;
 import org.jackhuang.hmcl.ui.FXUtils;
 import org.jackhuang.hmcl.util.AggregatedObservableList;
-import org.jackhuang.hmcl.util.javafx.MappedObservableList;
 
 public class TwoLineListItem extends VBox {
     private static final String DEFAULT_STYLE_CLASS = "two-line-list-item";
 
+    public static Label createTagLabel(String tag) {
+        Label tagLabel = new Label();
+        tagLabel.getStyleClass().add("tag");
+        tagLabel.setText(tag);
+        HBox.setMargin(tagLabel, new Insets(0, 8, 0, 0));
+        return tagLabel;
+    }
+
     private final StringProperty title = new SimpleStringProperty(this, "title");
-    private final ObservableList<String> tags = FXCollections.observableArrayList();
+    private final ObservableList<Label> tags = FXCollections.observableArrayList();
     private final StringProperty subtitle = new SimpleStringProperty(this, "subtitle");
 
-    private final ObservableList<Node> tagLabels;
     private final AggregatedObservableList<Node> firstLineChildren;
 
     public TwoLineListItem(String titleString, String subtitleString) {
@@ -58,16 +64,9 @@ public class TwoLineListItem extends VBox {
         lblTitle.getStyleClass().add("title");
         lblTitle.textProperty().bind(title);
 
-        tagLabels = MappedObservableList.create(tags, tag -> {
-            Label tagLabel = new Label();
-            tagLabel.getStyleClass().add("tag");
-            tagLabel.setText(tag);
-            HBox.setMargin(tagLabel, new Insets(0, 8, 0, 0));
-            return tagLabel;
-        });
         firstLineChildren = new AggregatedObservableList<>();
         firstLineChildren.appendList(FXCollections.singletonObservableList(lblTitle));
-        firstLineChildren.appendList(tagLabels);
+        firstLineChildren.appendList(tags);
         Bindings.bindContent(firstLine.getChildren(), firstLineChildren.getAggregatedList());
 
         Label lblSubtitle = new Label();
@@ -111,7 +110,11 @@ public class TwoLineListItem extends VBox {
         this.subtitle.set(subtitle);
     }
 
-    public ObservableList<String> getTags() {
+    public void addTag(String tag) {
+        getTags().add(createTagLabel(tag));
+    }
+
+    public ObservableList<Label> getTags() {
         return tags;
     }
 
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/download/VersionsPage.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/download/VersionsPage.java
index 9d1660570..062edd697 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/download/VersionsPage.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/download/VersionsPage.java
@@ -229,27 +229,28 @@ public final class VersionsPage extends Control implements WizardPage, Refreshab
             } else {
                 twoLineListItem.setSubtitle(null);
             }
+            twoLineListItem.getTags().clear();
 
             if (remoteVersion instanceof GameRemoteVersion) {
                 RemoteVersion.Type versionType = remoteVersion.getVersionType();
                 switch (versionType) {
                     case RELEASE:
-                        twoLineListItem.getTags().setAll(i18n("version.game.release"));
+                        twoLineListItem.addTag(i18n("version.game.release"));
                         imageView.setImage(VersionIconType.GRASS.getIcon());
                         break;
                     case PENDING:
                     case SNAPSHOT:
                         if (versionType == RemoteVersion.Type.SNAPSHOT
                                 && GameVersionNumber.asGameVersion(remoteVersion.getGameVersion()).isAprilFools()) {
-                            twoLineListItem.getTags().setAll(i18n("version.game.april_fools"));
+                            twoLineListItem.addTag(i18n("version.game.april_fools"));
                             imageView.setImage(VersionIconType.APRIL_FOOLS.getIcon());
                         } else {
-                            twoLineListItem.getTags().setAll(i18n("version.game.snapshot"));
+                            twoLineListItem.addTag(i18n("version.game.snapshot"));
                             imageView.setImage(VersionIconType.COMMAND.getIcon());
                         }
                         break;
                     default:
-                        twoLineListItem.getTags().setAll(i18n("version.game.old"));
+                        twoLineListItem.addTag(i18n("version.game.old"));
                         imageView.setImage(VersionIconType.CRAFT_TABLE.getIcon());
                         break;
                 }
@@ -276,7 +277,7 @@ public final class VersionsPage extends Control implements WizardPage, Refreshab
                 if (twoLineListItem.getSubtitle() == null)
                     twoLineListItem.setSubtitle(remoteVersion.getGameVersion());
                 else
-                    twoLineListItem.getTags().setAll(remoteVersion.getGameVersion());
+                    twoLineListItem.addTag(remoteVersion.getGameVersion());
             }
         }
     }
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/main/JavaManagementPage.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/main/JavaManagementPage.java
index 53a9c5804..d05433f9f 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/main/JavaManagementPage.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/main/JavaManagementPage.java
@@ -250,9 +250,9 @@ public final class JavaManagementPage extends ListPageBase<JavaManagementPage.Ja
             TwoLineListItem item = new TwoLineListItem();
             item.setTitle((java.isJDK() ? "JDK" : "JRE") + " " + java.getVersion());
             item.setSubtitle(java.getBinary().toString());
-            item.getTags().add(i18n("java.info.architecture") + ": " + java.getArchitecture().getDisplayName());
+            item.addTag(i18n("java.info.architecture") + ": " + java.getArchitecture().getDisplayName());
             if (vendor != null)
-                item.getTags().add(i18n("java.info.vendor") + ": " + vendor);
+                item.addTag(i18n("java.info.vendor") + ": " + vendor);
             BorderPane.setAlignment(item, Pos.CENTER);
             center.getChildren().setAll(item);
             root.setCenter(center);
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadListPage.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadListPage.java
index 7e109a4d1..cc5aceeef 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadListPage.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadListPage.java
@@ -523,9 +523,9 @@ public class DownloadListPage extends Control implements DecoratorPage, VersionP
 
                 // ListViewBehavior would consume ESC pressed event, preventing us from handling it, so we ignore it here
                 ignoreEvent(listView, KeyEvent.KEY_PRESSED, e -> e.getCode() == KeyCode.ESCAPE);
-                listView.setCellFactory(x -> new FloatListCell<RemoteMod>(listView) {
-                    TwoLineListItem content = new TwoLineListItem();
-                    ImageView imageView = new ImageView();
+                listView.setCellFactory(x -> new FloatListCell<>(listView) {
+                    private final TwoLineListItem content = new TwoLineListItem();
+                    private final ImageView imageView = new ImageView();
 
                     {
                         HBox container = new HBox(8);
@@ -542,10 +542,10 @@ public class DownloadListPage extends Control implements DecoratorPage, VersionP
                         ModTranslations.Mod mod = ModTranslations.getTranslationsByRepositoryType(getSkinnable().repository.getType()).getModByCurseForgeId(dataItem.getSlug());
                         content.setTitle(mod != null && I18n.isUseChinese() ? mod.getDisplayName() : dataItem.getTitle());
                         content.setSubtitle(dataItem.getDescription());
-                        content.getTags().setAll(dataItem.getCategories().stream()
+                        content.getTags().clear();
+                        dataItem.getCategories().stream()
                                 .map(category -> getSkinnable().getLocalizedCategory(category))
-                                .collect(Collectors.toList()));
-
+                                .forEach(content::addTag);
                         if (StringUtils.isNotBlank(dataItem.getIconUrl())) {
                             imageView.imageProperty().bind(FXUtils.newRemoteImage(dataItem.getIconUrl(), 40, 40, true, true));
                         }
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadPage.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadPage.java
index 441b1780d..4ef27ef16 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadPage.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/DownloadPage.java
@@ -228,9 +228,9 @@ public class DownloadPage extends Control implements DecoratorPage {
                 ModTranslations.Mod mod = getSkinnable().translations.getModByCurseForgeId(getSkinnable().addon.getSlug());
                 content.setTitle(mod != null && I18n.isUseChinese() ? mod.getDisplayName() : getSkinnable().addon.getTitle());
                 content.setSubtitle(getSkinnable().addon.getDescription());
-                content.getTags().setAll(getSkinnable().addon.getCategories().stream()
+                getSkinnable().addon.getCategories().stream()
                         .map(category -> getSkinnable().page.getLocalizedCategory(category))
-                        .collect(Collectors.toList()));
+                        .forEach(content::addTag);
                 descriptionPane.getChildren().add(content);
 
                 if (getSkinnable().mod != null) {
@@ -353,10 +353,9 @@ public class DownloadPage extends Control implements DecoratorPage {
                 ModTranslations.Mod mod = ModTranslations.getTranslationsByRepositoryType(page.repository.getType()).getModByCurseForgeId(addon.getSlug());
                 content.setTitle(mod != null && I18n.isUseChinese() ? mod.getDisplayName() : addon.getTitle());
                 content.setSubtitle(addon.getDescription());
-                content.getTags().setAll(addon.getCategories().stream()
+                addon.getCategories().stream()
                         .map(page::getLocalizedCategory)
-                        .collect(Collectors.toList()));
-
+                        .forEach(content::addTag);
                 if (StringUtils.isNotBlank(addon.getIconUrl())) {
                     imageView.imageProperty().bind(FXUtils.newRemoteImage(addon.getIconUrl(), 40, 40, true, true));
                 }
@@ -389,15 +388,15 @@ public class DownloadPage extends Control implements DecoratorPage {
 
                     switch (dataItem.getVersionType()) {
                         case Alpha:
-                            content.getTags().add(i18n("mods.channel.alpha"));
+                            content.addTag(i18n("mods.channel.alpha"));
                             graphicPane.getChildren().setAll(SVG.ALPHA_CIRCLE.createIcon(Theme.blackFill(), 24));
                             break;
                         case Beta:
-                            content.getTags().add(i18n("mods.channel.beta"));
+                            content.addTag(i18n("mods.channel.beta"));
                             graphicPane.getChildren().setAll(SVG.BETA_CIRCLE.createIcon(Theme.blackFill(), 24));
                             break;
                         case Release:
-                            content.getTags().add(i18n("mods.channel.release"));
+                            content.addTag(i18n("mods.channel.release"));
                             graphicPane.getChildren().setAll(SVG.RELEASE_CIRCLE.createIcon(Theme.blackFill(), 24));
                             break;
                     }
@@ -405,22 +404,22 @@ public class DownloadPage extends Control implements DecoratorPage {
                     for (ModLoaderType modLoaderType : dataItem.getLoaders()) {
                         switch (modLoaderType) {
                             case FORGE:
-                                content.getTags().add(i18n("install.installer.forge"));
+                                content.addTag(i18n("install.installer.forge"));
                                 break;
                             case CLEANROOM:
-                                content.getTags().add(i18n("install.installer.cleanroom"));
+                                content.addTag(i18n("install.installer.cleanroom"));
                                 break;
                             case NEO_FORGED:
-                                content.getTags().add(i18n("install.installer.neoforge"));
+                                content.addTag(i18n("install.installer.neoforge"));
                                 break;
                             case FABRIC:
-                                content.getTags().add(i18n("install.installer.fabric"));
+                                content.addTag(i18n("install.installer.fabric"));
                                 break;
                             case LITE_LOADER:
-                                content.getTags().add(i18n("install.installer.liteloader"));
+                                content.addTag(i18n("install.installer.liteloader"));
                                 break;
                             case QUILT:
-                                content.getTags().add(i18n("install.installer.quilt"));
+                                content.addTag(i18n("install.installer.quilt"));
                                 break;
                         }
                     }
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/GameItemSkin.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/GameItemSkin.java
index a09bdd58d..b7b79f621 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/GameItemSkin.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/GameItemSkin.java
@@ -47,11 +47,9 @@ public class GameItemSkin extends SkinBase<GameItem> {
         TwoLineListItem item = new TwoLineListItem();
         item.titleProperty().bind(skinnable.titleProperty());
         FXUtils.onChangeAndOperate(skinnable.tagProperty(), tag -> {
-            if (StringUtils.isNotBlank(tag)) {
-                item.getTags().setAll(tag);
-            } else {
-                item.getTags().clear();
-            }
+            item.getTags().clear();
+            if (StringUtils.isNotBlank(tag))
+                item.addTag(tag);
         });
         item.subtitleProperty().bind(skinnable.subtitleProperty());
         BorderPane.setAlignment(item, Pos.CENTER);
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/ModListPageSkin.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/ModListPageSkin.java
index 4e7a12489..28f5f4cbb 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/ModListPageSkin.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/ModListPageSkin.java
@@ -395,7 +395,7 @@ class ModListPageSkin extends SkinBase<ModListPage> {
             TwoLineListItem title = new TwoLineListItem();
             title.setTitle(modInfo.getModInfo().getName());
             if (StringUtils.isNotBlank(modInfo.getModInfo().getVersion())) {
-                title.getTags().setAll(modInfo.getModInfo().getVersion());
+                title.addTag(modInfo.getModInfo().getVersion());
             }
             title.setSubtitle(FileUtils.getName(modInfo.getModInfo().getFile()));
 
@@ -442,9 +442,10 @@ class ModListPageSkin extends SkinBase<ModListPage> {
                                         default:
                                             continue;
                                     }
-                                    List<String> tags = title.getTags();
-                                    if (!tags.contains(loaderName)) {
-                                        tags.add(loaderName);
+                                    if (title.getTags()
+                                            .stream()
+                                            .noneMatch(it -> it.getText().equals(loaderName))) {
+                                        title.addTag(loaderName);
                                     }
                                 }
 
@@ -551,26 +552,26 @@ class ModListPageSkin extends SkinBase<ModListPage> {
             content.getTags().clear();
             switch (dataItem.getModInfo().getModLoaderType()) {
                 case FORGE:
-                    content.getTags().add(i18n("install.installer.forge"));
+                    content.addTag(i18n("install.installer.forge"));
                     break;
                 case CLEANROOM:
-                    content.getTags().add(i18n("install.installer.cleanroom"));
+                    content.addTag(i18n("install.installer.cleanroom"));
                     break;
                 case NEO_FORGED:
-                    content.getTags().add(i18n("install.installer.neoforge"));
+                    content.addTag(i18n("install.installer.neoforge"));
                     break;
                 case FABRIC:
-                    content.getTags().add(i18n("install.installer.fabric"));
+                    content.addTag(i18n("install.installer.fabric"));
                     break;
                 case LITE_LOADER:
-                    content.getTags().add(i18n("install.installer.liteloader"));
+                    content.addTag(i18n("install.installer.liteloader"));
                     break;
                 case QUILT:
-                    content.getTags().add(i18n("install.installer.quilt"));
+                    content.addTag(i18n("install.installer.quilt"));
                     break;
             }
             if (dataItem.getMod() != null && I18n.isUseChinese()) {
-                content.getTags().add(dataItem.getMod().getDisplayName());
+                content.addTag(dataItem.getMod().getDisplayName());
             }
             content.setSubtitle(dataItem.getSubtitle());
             if (booleanProperty != null) {
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldBackupsPage.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldBackupsPage.java
index 67562e3aa..c66d35886 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldBackupsPage.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldBackupsPage.java
@@ -245,7 +245,8 @@ public final class WorldBackupsPage extends ListPageBase<WorldBackupsPage.Backup
                     item.setTitle(parseColorEscapes(skinnable.getBackupWorld().getWorldName()));
                 item.setSubtitle(formatDateTime(skinnable.getBackupTime()) + (skinnable.count == 0 ? "" : " (" + skinnable.count + ")"));
 
-                if (world.getGameVersion() != null) item.getTags().add(world.getGameVersion());
+                if (world.getGameVersion() != null)
+                    item.addTag(world.getGameVersion());
             }
 
             {
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldListItemSkin.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldListItemSkin.java
index 9a0d75a89..3551c5ae4 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldListItemSkin.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/versions/WorldListItemSkin.java
@@ -76,9 +76,9 @@ public final class WorldListItemSkin extends SkinBase<WorldListItem> {
             item.setSubtitle(i18n("world.datetime", formatDateTime(Instant.ofEpochMilli(world.getLastPlayed())), world.getGameVersion() == null ? i18n("message.unknown") : world.getGameVersion()));
 
             if (world.getGameVersion() != null)
-                item.getTags().add(world.getGameVersion());
+                item.addTag(world.getGameVersion());
             if (world.isLocked())
-                item.getTags().add(i18n("world.locked"));
+                item.addTag(i18n("world.locked"));
         }
 
         {
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/util/AggregatedObservableList.java b/HMCL/src/main/java/org/jackhuang/hmcl/util/AggregatedObservableList.java
index 0fe0d89fb..bedbfa0a7 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/util/AggregatedObservableList.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/util/AggregatedObservableList.java
@@ -28,10 +28,10 @@ import java.util.function.Function;
 
 public final class AggregatedObservableList<T> {
 
-    protected final List<ObservableList<T>> lists = new ArrayList<>();
-    final private List<Integer> sizes = new ArrayList<>();
-    final private List<InternalListModificationListener> listeners = new ArrayList<>();
-    final protected ObservableList<T> aggregatedList = FXCollections.observableArrayList();
+    private final List<ObservableList<? extends T>> lists = new ArrayList<>();
+    private final List<Integer> sizes = new ArrayList<>();
+    private final List<InternalListModificationListener> listeners = new ArrayList<>();
+    private final ObservableList<T> aggregatedList = FXCollections.observableArrayList();
 
     public AggregatedObservableList() {
 
@@ -46,7 +46,7 @@ public final class AggregatedObservableList<T> {
         return aggregatedList;
     }
 
-    public void appendList(@NotNull ObservableList<T> list) {
+    public void appendList(@NotNull ObservableList<? extends T> list) {
         assert !lists.contains(list) : "List is already contained: " + list;
         lists.add(list);
         final InternalListModificationListener listener = new InternalListModificationListener(list);
@@ -59,7 +59,7 @@ public final class AggregatedObservableList<T> {
                 "lists.size=" + lists.size() + " not equal to sizes.size=" + sizes.size() + " or not equal to listeners.size=" + listeners.size();
     }
 
-    public void prependList(@NotNull ObservableList<T> list) {
+    public void prependList(@NotNull ObservableList<? extends T> list) {
         assert !lists.contains(list) : "List is already contained: " + list;
         lists.add(0, list);
         final InternalListModificationListener listener = new InternalListModificationListener(list);
@@ -72,7 +72,7 @@ public final class AggregatedObservableList<T> {
                 "lists.size=" + lists.size() + " not equal to sizes.size=" + sizes.size() + " or not equal to listeners.size=" + listeners.size();
     }
 
-    public void removeList(@NotNull ObservableList<T> list) {
+    public void removeList(@NotNull ObservableList<? extends T> list) {
         assert lists.size() == sizes.size() && lists.size() == listeners.size() :
                 "lists.size=" + lists.size() + " not equal to sizes.size=" + sizes.size() + " or not equal to listeners.size=" + listeners.size();
         final int index = lists.indexOf(list);
@@ -98,7 +98,7 @@ public final class AggregatedObservableList<T> {
      * @param list the list in question
      * @return the start index of this list in the aggregated List
      */
-    private int getStartIndex(@NotNull ObservableList<T> list) {
+    private int getStartIndex(@NotNull ObservableList<? extends T> list) {
         int startIndex = 0;
         //System.out.println("=== searching startIndex of " + list);
         assert lists.size() == sizes.size() : "lists.size=" + lists.size() + " not equal to sizes.size=" + sizes.size();
@@ -120,7 +120,7 @@ public final class AggregatedObservableList<T> {
      * @param startIndex the start of the list (retrieve with {@link #getStartIndex(ObservableList)}
      * @return the end index of this list in the aggregated List
      */
-    private int getEndIndex(@NotNull ObservableList<T> list, int startIndex) {
+    private int getEndIndex(@NotNull ObservableList<? extends T> list, int startIndex) {
         assert lists.size() == sizes.size() : "lists.size=" + lists.size() + " not equal to sizes.size=" + sizes.size();
         final int index = lists.indexOf(list);
         return startIndex + sizes.get(index) - 1;
@@ -129,9 +129,9 @@ public final class AggregatedObservableList<T> {
     private final class InternalListModificationListener implements ListChangeListener<T> {
 
         @NotNull
-        private final ObservableList<T> list;
+        private final ObservableList<? extends T> list;
 
-        public InternalListModificationListener(@NotNull ObservableList<T> list) {
+        public InternalListModificationListener(@NotNull ObservableList<? extends T> list) {
             this.list = list;
         }