Hello 
Steps:
1 - Create A widget bp to be the Menu. (Menu)
2 - Create another widget bp to be the button. (MyButton)
2a - Inside the MyButton widget bp: (image below)
3 - In the Menu widget, add a Scroll Box, inside the Scroll Box add some buttons inside the Scroll Box, in our case, MyButton, can found him in the “User Created” menu in Palette.
3a - Go to the MyButton hovered event and add the “Set Keyboard Focus” node and link MyButton to the target in the “Set Keyboard Focus” node.
4 - Open the “FirstPersonGameMode” and add: EventBeginPlay > Create Menu Widget > Add to Viewport > Set Input Mode UI Only > Show Mouse Cursor > Set Game Pause (image below).
To make sure, get the same MyButton and add some buttons outside the Scroll Box, you will see that this buttons can be clicked by Keyboard or Joystick/Gamepad but the same MyButtons inside the Scroll Box, can’t.
ps: I added the Pressed event in MyButton, and the keyboard dont work in the first time…but if i move to the button outside the Scroll Box and back to the button inside the Scroll Box, the button, work only 1 time. And the button outside the ScrollBox works fine with only the clicked event (using keyboard to click).
I upload the project in Google Drive, give a luck, cause my English are not the best to explain this kind of stuff xD
[Google Drive UE file.][4]
If need anything else, just say, and thanks
