The mouse side buttons, or mouse buttons 4 and 5, will not work for binding, and mouse button 4 wont let you cancel things as it use too.

The mouse buttons 4 and 5 have stopped working in minecraft bedrock I can't rebind them or use them, I have in the past used these keys and then they stopped working in chests to get out of them quickly and out of invintory as it has done in the past.