Protostar does not assign for some reason

[uglyeoin]

Steps to reproduce the issue

Create Joomla! install.
Use Blog dummy content
Open protostar from backend templates > Protostar
Try not to assign it to something on the main menu when on desktop

Expected result

can assign to menu items or unassign

Actual result

Can't click on the right hand box

Here's a nice video
https://www.dropbox.com/s/h0hbch8hi07udzf/protostar.mp4?dl=0

System information (as much as possible)

systeminfo-2018-06-08T16_22_34-05_00.txt

Additional comments

Brand new install. Only Akeeba Backup is installed.

[joomla-cms-bot]

Set to "closed" on behalf of @Quy by The JTracker Application at issues.joomla.org/joomla-cms/20696

[Quy]

Fixed in #20542 for v3.8.9

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/20696.}

[uglyeoin]

Thanks, great job.

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/20696.}