Can't hold alt to see ability upgrades anymore

You used to be able to hold ALT, and your mouse would unlock and you could mouse over your abilities and read about them. You could also ping the map to communicate with teammates with ALT. You can still hold ALT and press the number keys to upgrade your abilities, but ALT doesn't let you mouse over stuff anymore. You can still unstick the mouse with TAB, but that brings up the whole scoreboard UI. Why did Valve straight up remove a functionality from the game?