How to delete a widget
Deleting a widget removes it from every dashboard it is used in, and it also deletes the widget entirely from Apex.
Note: System widgets cannot be deleted from Apex.
To delete a widget:
1. In the web interface, click Configuration > Widget Library.
2. Select a widget from the leftmost pane by clicking it.
The widget is now editable.
3. Click the garbage can icon .
4. Confirm the deletion by clicking Yes.
 
The widget was successfully deleted from Apex.