Unable to click Configure Realm button
(note your issue "affected versions" isn't complete - this is version 1.12 but I couldn't pick that)
After launching Minecraft and choosing the "Minecraft Realms" option, I am see the list of available realms (the trial one I signed up for).
I can highlight the line to select it and click the Play button.
I can hover over the Configure Realm button and it changes colour, but it cannot be clicked.When clicking nothing happens.
This is specific to this computer as it works fine on another PC.
Environment
Windows 10 Pro 1703. 16GM RAM. NVidia GeForce GTX 760 (GeForce driver 382.05 2017-05-03)
Created Issue:
Unable to click Configure Realm button
(note your issue "affected versions" isn't complete - this is version 1.12 but I couldn't pick that)
After launching Minecraft and choosing the "Minecraft Realms" option, I am see the list of available realms (the trial one I signed up for).
I can highlight the line to select it and click the Play button.
I can hover over the Configure Realm button and it changes colour, but it cannot be clicked.When clicking nothing happens.
This is specific to this computer as it works fine on another PC.
Environment
Windows 10 Pro 1703. 16GM RAM. NVidia GeForce GTX 760 (GeForce driver 382.05 2017-05-03)

I also have the same issue although it doesn't appear to be specific to one pc.
Restart your computer and look if the problem is solved. For me a restart is the solution.
Cleaning up old tickets: This ticket has not been updated recently (~1 year+) so is being closed as Cannot Reproduce. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines.
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