Hard to describe this issue clearly but bear with me...
Very new Windows computer, running Windows 10, installed BZFlag 2.4.8. I start the game but the mouse pointer isn't aligned properly with the mouse box. Specifically, the neutral position of the pointer is at the far right, bottom of the screen. In other words, the place where the tank is stopped is when the mouse pointer is far right, bottom. If I try to position the mouse inside the mouse box where it should be stopped, the tank moves forward and turns left.
I can't find any setting to define where the neutral position of the mouse pointer should be.
I have tried running the game in Windows 7 and Windows XP compatibility mode, with no improvement. Then I installed version 2.4.6 and tried it, with no improvement.
One other thing, this new computer has a very high screen resolution (3840x2160). I'm suspecting that the game is going something incompatible with a resolution that high.