Problems Using Mouse In-Game

Hello, I have recently purchased an Acer monitor xfa240 144hz and am having new problems when playing some games. If I use the tab, esc, or other combinations of keys that would allow me to then see and use my mouse in-game, I suddenly loose frames and momentarily cannot see my mouse. I've not had this problem in all games, but most. Squad, for example, seems to work fine. Rocket League and Day of Infamy, however, have this problem every time I hit esc or tab. I'd appreciate any information that would help me research and solve this problem. The only link to the monitor is that it hadn't happened with my old monitors. I do run a dual monitor setup.