diff --git a/app/src/main/java/org/tasks/tags/CheckBoxTriStates.java b/app/src/main/java/org/tasks/tags/CheckBoxTriStates.java
deleted file mode 100644
index 0f5fae47d..000000000
--- a/app/src/main/java/org/tasks/tags/CheckBoxTriStates.java
+++ /dev/null
@@ -1,172 +0,0 @@
-package org.tasks.tags;
-
-import static org.tasks.preferences.ResourceResolver.getData;
-
-import android.content.Context;
-import android.graphics.drawable.Drawable;
-import android.os.Parcel;
-import android.os.Parcelable;
-import android.util.AttributeSet;
-import android.widget.CompoundButton;
-import androidx.annotation.Nullable;
-import androidx.appcompat.widget.AppCompatCheckBox;
-import androidx.core.content.res.ResourcesCompat;
-import org.tasks.R;
-
-public class CheckBoxTriStates extends AppCompatCheckBox {
-
-  private int alpha;
-  private State state;
-  private OnCheckedChangeListener clientListener;
-
-  private final OnCheckedChangeListener privateListener =
-      new CompoundButton.OnCheckedChangeListener() {
-
-        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
-          switch (state) {
-            case PARTIALLY_CHECKED:
-            case UNCHECKED:
-              setState(State.CHECKED, true);
-              break;
-            case CHECKED:
-              setState(State.UNCHECKED, true);
-              break;
-          }
-        }
-      };
-
-  public CheckBoxTriStates(Context context) {
-    super(context);
-    init();
-  }
-
-  public CheckBoxTriStates(Context context, AttributeSet attrs) {
-    super(context, attrs);
-    init();
-  }
-
-  public CheckBoxTriStates(Context context, AttributeSet attrs, int defStyleAttr) {
-    super(context, attrs, defStyleAttr);
-    init();
-  }
-
-  public void setState(State state, boolean notify) {
-    if (this.state != state) {
-      this.state = state;
-
-      if (notify && this.clientListener != null) {
-        this.clientListener.onCheckedChanged(this, this.isChecked());
-      }
-    }
-
-    updateBtn();
-  }
-
-  @Override
-  public void setOnCheckedChangeListener(@Nullable OnCheckedChangeListener listener) {
-    if (this.privateListener != listener) {
-      this.clientListener = listener;
-    }
-
-    super.setOnCheckedChangeListener(privateListener);
-  }
-
-  @Override
-  public Parcelable onSaveInstanceState() {
-    Parcelable superState = super.onSaveInstanceState();
-
-    SavedState ss = new SavedState(superState);
-
-    ss.state = state.ordinal();
-
-    return ss;
-  }
-
-  @Override
-  public void onRestoreInstanceState(Parcelable state) {
-    SavedState ss = (SavedState) state;
-    super.onRestoreInstanceState(ss.getSuperState());
-    this.state = State.values()[ss.state];
-    updateBtn();
-    requestLayout();
-  }
-
-  private void init() {
-    alpha = (int) (255 * ResourcesCompat.getFloat(getResources(), R.dimen.alpha_secondary));
-    setState(State.UNCHECKED, false);
-    setOnCheckedChangeListener(this.privateListener);
-  }
-
-  private void updateBtn() {
-    int btnDrawable;
-    int alpha = 255;
-    switch (state) {
-      case PARTIALLY_CHECKED:
-        btnDrawable = R.drawable.ic_indeterminate_check_box_24px;
-        break;
-      case CHECKED:
-        btnDrawable = R.drawable.ic_outline_check_box_24px;
-        break;
-      default:
-        btnDrawable = R.drawable.ic_outline_check_box_outline_blank_24px;
-        alpha = this.alpha;
-        break;
-    }
-    Drawable original = getContext().getDrawable(btnDrawable);
-    Drawable drawable;
-    int color = state == State.UNCHECKED
-        ? getContext().getColor(R.color.icon_tint)
-        : getData(getContext(), androidx.appcompat.R.attr.colorAccent);
-    drawable = original.mutate();
-    drawable.setTint(color);
-    drawable.setAlpha(alpha);
-    setButtonDrawable(drawable);
-  }
-
-  public enum State {
-    PARTIALLY_CHECKED,
-    CHECKED,
-    UNCHECKED
-  }
-
-  static class SavedState extends BaseSavedState {
-    public static final Parcelable.Creator<SavedState> CREATOR =
-        new Parcelable.Creator<>() {
-          @Override
-          public SavedState createFromParcel(Parcel in) {
-            return new SavedState(in);
-          }
-
-          @Override
-          public SavedState[] newArray(int size) {
-            return new SavedState[size];
-          }
-        };
-
-    int state;
-
-    SavedState(Parcelable superState) {
-      super(superState);
-    }
-
-    private SavedState(Parcel in) {
-      super(in);
-      state = in.readInt();
-    }
-
-    @Override
-    public void writeToParcel(Parcel out, int flags) {
-      super.writeToParcel(out, flags);
-      out.writeValue(state);
-    }
-
-    @Override
-    public String toString() {
-      return "CheckboxTriState.SavedState{"
-          + Integer.toHexString(System.identityHashCode(this))
-          + " state="
-          + state
-          + "}";
-    }
-  }
-}
diff --git a/app/src/main/java/org/tasks/tags/TagDiffCallback.java b/app/src/main/java/org/tasks/tags/TagDiffCallback.java
deleted file mode 100644
index 927ab5bee..000000000
--- a/app/src/main/java/org/tasks/tags/TagDiffCallback.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package org.tasks.tags;
-
-import androidx.annotation.NonNull;
-import androidx.recyclerview.widget.DiffUtil;
-import java.util.Objects;
-import org.tasks.data.TagData;
-
-class TagDiffCallback extends DiffUtil.ItemCallback<TagData> {
-
-  @Override
-  public boolean areItemsTheSame(@NonNull TagData oldItem, @NonNull TagData newItem) {
-    return Objects.equals(oldItem.getId(), newItem.getId());
-  }
-
-  @Override
-  public boolean areContentsTheSame(@NonNull TagData oldItem, @NonNull TagData newItem) {
-    return oldItem.equals(newItem);
-  }
-}