diff --git a/core/events/ui_events.js b/core/events/events_ui.js
similarity index 64%
rename from core/events/ui_events.js
rename to core/events/events_ui.js
index 5d649a22f..be8500b33 100644
--- a/core/events/ui_events.js
+++ b/core/events/events_ui.js
@@ -5,59 +5,22 @@
  */
 
 /**
- * @fileoverview Events fired as a result of UI actions in Blockly's editor.
+ * @fileoverview (Deprecated) Events fired as a result of UI actions in
+ * Blockly's editor.
  * @author fraser@google.com (Neil Fraser)
  */
 'use strict';
 
 goog.provide('Blockly.Events.Ui');
-goog.provide('Blockly.Events.UiBase');
 
 goog.require('Blockly.Events');
-goog.require('Blockly.Events.Abstract');
+goog.require('Blockly.Events.UiBase');
 goog.require('Blockly.registry');
 goog.require('Blockly.utils.object');
 
 goog.requireType('Blockly.Block');
 
 
-/**
- * Base class for a UI event.
- * UI events are events that don't need to be sent over the wire for multi-user
- * editing to work (e.g. scrolling the workspace, zooming, opening toolbox
- * categories).
- * UI events do not undo or redo.
- * @param {string=} opt_workspaceId The workspace identifier for this event.
- *    Undefined for a blank event.
- * @extends {Blockly.Events.Abstract}
- * @constructor
- */
-Blockly.Events.UiBase = function(opt_workspaceId) {
-  Blockly.Events.UiBase.superClass_.constructor.call(this);
-
-  /**
-   * Whether or not the event is blank (to be populated by fromJson).
-   * @type {boolean}
-   */
-  this.isBlank = typeof opt_workspaceId == 'undefined';
-
-  /**
-   * The workspace identifier for this event.
-   * @type {string}
-   */
-  this.workspaceId = opt_workspaceId ? opt_workspaceId : '';
-
-  // UI events do not undo or redo.
-  this.recordUndo = false;
-};
-Blockly.utils.object.inherits(Blockly.Events.UiBase, Blockly.Events.Abstract);
-
-/**
- * Whether or not the event is a UI event.
- * @type {boolean}
- */
-Blockly.Events.UiBase.prototype.isUiEvent = true;
-
 /**
  * Class for a UI event.
  * @param {?Blockly.Block=} opt_block The affected block.  Null for UI events
@@ -116,4 +79,4 @@ Blockly.Events.Ui.prototype.fromJson = function(json) {
 };
 
 Blockly.registry.register(Blockly.registry.Type.EVENT, Blockly.Events.UI,
-    Blockly.Events.Ui);
+    Blockly.Events.Ui);
\ No newline at end of file
diff --git a/core/events/events_ui_base.js b/core/events/events_ui_base.js
new file mode 100644
index 000000000..b286b9283
--- /dev/null
+++ b/core/events/events_ui_base.js
@@ -0,0 +1,58 @@
+/**
+ * @license
+ * Copyright 2020 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Base class for events fired as a result of UI actions in
+ * Blockly's editor.
+ * @author fraser@google.com (Neil Fraser)
+ */
+'use strict';
+
+goog.provide('Blockly.Events.UiBase');
+
+goog.require('Blockly.Events');
+goog.require('Blockly.Events.Abstract');
+goog.require('Blockly.utils.object');
+
+goog.requireType('Blockly.Block');
+
+
+/**
+ * Base class for a UI event.
+ * UI events are events that don't need to be sent over the wire for multi-user
+ * editing to work (e.g. scrolling the workspace, zooming, opening toolbox
+ * categories).
+ * UI events do not undo or redo.
+ * @param {string=} opt_workspaceId The workspace identifier for this event.
+ *    Undefined for a blank event.
+ * @extends {Blockly.Events.Abstract}
+ * @constructor
+ */
+Blockly.Events.UiBase = function(opt_workspaceId) {
+  Blockly.Events.UiBase.superClass_.constructor.call(this);
+
+  /**
+   * Whether or not the event is blank (to be populated by fromJson).
+   * @type {boolean}
+   */
+  this.isBlank = typeof opt_workspaceId == 'undefined';
+
+  /**
+   * The workspace identifier for this event.
+   * @type {string}
+   */
+  this.workspaceId = opt_workspaceId ? opt_workspaceId : '';
+
+  // UI events do not undo or redo.
+  this.recordUndo = false;
+};
+Blockly.utils.object.inherits(Blockly.Events.UiBase, Blockly.Events.Abstract);
+
+/**
+ * Whether or not the event is a UI event.
+ * @type {boolean}
+ */
+Blockly.Events.UiBase.prototype.isUiEvent = true;
diff --git a/tests/deps.js b/tests/deps.js
index 4e2796458..9d4b8a6bd 100644
--- a/tests/deps.js
+++ b/tests/deps.js
@@ -49,12 +49,13 @@ goog.addDependency('../../core/events/events_selected.js', ['Blockly.Events.Sele
 goog.addDependency('../../core/events/events_theme_change.js', ['Blockly.Events.ThemeChange'], ['Blockly.Events', 'Blockly.Events.UiBase', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/events/events_toolbox_item_select.js', ['Blockly.Events.ToolboxItemSelect'], ['Blockly.Events', 'Blockly.Events.UiBase', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/events/events_trashcan_open.js', ['Blockly.Events.TrashcanOpen'], ['Blockly.Events', 'Blockly.Events.UiBase', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
+goog.addDependency('../../core/events/events_ui.js', ['Blockly.Events.Ui'], ['Blockly.Events', 'Blockly.Events.UiBase', 'Blockly.registry', 'Blockly.utils.object']);
+goog.addDependency('../../core/events/events_ui_base.js', ['Blockly.Events.UiBase'], ['Blockly.Events', 'Blockly.Events.Abstract', 'Blockly.utils.object']);
 goog.addDependency('../../core/events/events_var_base.js', ['Blockly.Events.VarBase'], ['Blockly.Events.Abstract', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/events/events_var_create.js', ['Blockly.Events.VarCreate'], ['Blockly.Events', 'Blockly.Events.VarBase', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/events/events_var_delete.js', ['Blockly.Events.VarDelete'], ['Blockly.Events', 'Blockly.Events.VarBase', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/events/events_var_rename.js', ['Blockly.Events.VarRename'], ['Blockly.Events', 'Blockly.Events.VarBase', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/events/events_viewport.js', ['Blockly.Events.ViewportChange'], ['Blockly.Events', 'Blockly.Events.UiBase', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
-goog.addDependency('../../core/events/ui_events.js', ['Blockly.Events.Ui', 'Blockly.Events.UiBase'], ['Blockly.Events', 'Blockly.Events.Abstract', 'Blockly.registry', 'Blockly.utils.object']);
 goog.addDependency('../../core/events/workspace_events.js', ['Blockly.Events.FinishedLoading'], ['Blockly.Events', 'Blockly.Events.Abstract', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/events/ws_comment_events.js', ['Blockly.Events.CommentBase', 'Blockly.Events.CommentChange', 'Blockly.Events.CommentCreate', 'Blockly.Events.CommentDelete', 'Blockly.Events.CommentMove'], ['Blockly.Events', 'Blockly.Events.Abstract', 'Blockly.Xml', 'Blockly.registry', 'Blockly.utils.Coordinate', 'Blockly.utils.object', 'Blockly.utils.xml']);
 goog.addDependency('../../core/extensions.js', ['Blockly.Extensions'], ['Blockly.utils'], {'lang': 'es6', 'module': 'goog'});