After updating to 7.x-1.12 content is edited as expected. However, when attempting to edit a block, the WYSIWYG editor flashes on screen for a brief second and the screen goes black. The browser is in wait mode for the server but nothing happens.
If I configure CKEditor to default to plain text editor, the HTML5 code shows up and edits are handled as entered. If I click on the rich text editor to switch, the screen goes blank and nothing happens.
Environment Drupal 7.18