How to stop MacOS automatically jumping out of full screen programs?

When playing a video game that takes up the whole screen, MacOS will regularly, several times during a session, hide the game window to highlight another program (an arbitrary one that has been used before the game) that has a selected text box which shows the white-on-blue language marker. How can MacOS be stopped from jumping out of full screen programs? If a game has a text box, the white-on-blue language marker will show up there moments before the jump out of the game. Making any action in the in-game text box will stop the jump (until the marker shows up again after some period). These automatic jumps out of the game are more probable if the user has manually done the jump themselves in a session. What feature is this and how can it be disabled?