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**Do you want to request a *feature* or report a *bug*?**

bug

**What is the current behavior?**

`onMouseEnter` is fired on `disabled` buttons.

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem. Your bug will get fixed much faster if we can run your code and it doesn't have dependencies other than React. Paste the link to your JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new) example below:**

https://codesandbox.io/s/react-onmouseenter-on-disabled-buttons-fskwd

**What is the expected behavior?**

`onMouseEnter` shouldn't be triggered on `disabled` buttons.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**

React 16.11.0 (not sure when it started to happen)
Chrome/MacOS

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 * @flow
 */
import invariant from 'shared/invariant';
import {
  injectEventPluginOrder,
  injectEventPluginsByName,
  plugins,
} from './EventPluginRegistry';
import {getFiberCurrentPropsFromNode} from './EventPluginUtils';
import accumulateInto from './accumulateInto';
import {runEventsInBatch} from './EventBatching';
import type {PluginModule} from './PluginModuleType';
import type {ReactSyntheticEvent} from './ReactSyntheticEventType';
import type {Fiber} from 'react-reconciler/src/ReactFiber';
import type {AnyNativeEvent} from './PluginModuleType';
import type {TopLevelType} from './TopLevelEventTypes';
import type {EventSystemFlags} from 'legacy-events/EventSystemFlags';
function isInteractive(tag) {