Trouble with mouse controller between levels

Hi guys. I was creating a map where the user controls the navigation around the space by using mouse and keyboard controls, such as, W/A/S/D/Q/E to move around and RMB-click (right mouse button) to view around. Without the RMB-click, the user’s view is always fixed.

Also, there are buttons which I have included for the user to interact with. These controls are desired and successfully achieved.

Here’s the issue which I encounter and could not figure out on how to solve. I have added another level which is suppose to be like a menu page. Upon launching the game, it will start with a simple menu page which has 2 buttons, Enter or Quit. When user LMB-click the Enter button, it will bring to the level which has the map. In the following level, when I move the mouse around (no RMB/LMB click), I am able to look around the space. This is not desired.

Only when I either click the RMB or LMB, it will go back to desired control (which I mentioned earlier).

How do I go about in solving this mouse control issue? Thank you in advance.