Main Menu problem

Hello, I have made a simple menu with a sub-menu within. When I’m in the sub-menu, I click on the back button so I return to the main menu, but when I click resume I click to use mouse and it won’t work, but when I hold it, it works fine. I have tried just opening the menu and resuming, and everything works fine. It appears it only occurs when I use the “back” button. How do fix this? Blueprint for the back button:

Bump. Any help?