Cannot close "block" window

The X to close the patron-block add/edit pane does not work, making it impossible to close the "New/edit patron block" pane.

STEPS:

1. Visit Users
2. Choose an active user
3. Click the "Patron blocks" accordion to expand it
4. Click the "Create block" button
5. Click the "Close-X" icon at top left

Expected behavior

Return to the SearchAndSort view with search results and patron details

Actual behavior

Nada. You're stuck, unless you choose to create the block and click the "Close & save" button.

The same behavior is present when editing an existing block. The "Close X" does not function. The only option is to click the back button or make a change to the block in order to activate the "Close & save" button.