CTRL+R does not hide the Query Result window in SSMS

1. Open the Tools menu select Options...
2. Under the Environment node click on the Keyboard node
3. Click the Reset button
4. Click Yes on the dialog that pops up

That should solve your issue. If not please add a comment to this thread with details about your issue.

This is missing in SSMS 2016 as well, assign it manually as shown below.

In my case, under Keyboard Settings, I searched for Window.ResultsPane. My default keyboard shortcut was Ctrl + R, and doing Ctrl + R was not working for me. I have set it to Ctrl + R, Ctrl + R and now it's working fine for me. Doing a reset is not a good idea since it would be removing any and all custom settings set by the user.