Steps to reproduce:

Pick any inner template and edit it
Click the Content tab
Click the Edit Content button
Change the dropdown from 'General' to any other widget category

The first tooltip to render for the widget list is now frozen on the display. Other tooltips will display and disappear, however the first one to render stays until you leave the entire page.

This only happens if the mouse is hovering a widget as the widget list is refreshed from the change in dropdown selection. If you move the mouse away from the widget list until the widget list is refreshed, the issue will not occur.

In other words, if you change the dropdown and make a tooltip render before the widget list refreshes, the refresh causes the previous tooltip to freeze on the page. Most likely to happen if you choose one first few selections in the dropdown as your mouse will then be sitting atop a widget when the dropdown disappears after selection.

Clicking in the middle of the dropdown where the mouse will not hover a widget seems to avoid the issue.

See video below:
https://www.screencast.com/t/6jHSYOBd