Mouse cursor on main menu

For some reasons when I play the Menu level I have to press once the left click of my mouse anywhere on the screen in order to be able to use the buttons of the Menu.Can I solve it from blueprints or it won`t happen if I build the game and install it on my pc?

You need to use “Set input mode UI Only”.
But do not forget about setting input mode back to the game.


Thank you,sir!