DE2 push buttons question

I have changed the process like this:

    buttons_process:process (key)
    begin
            if ((key(0) = '0' and key(0)'event)) then
                run <= not run; -- switch ON/OFF does't work properly - why ??
                reset <= '0';
            end if;
            if (key(1) = '0') then
                hex6    <= "1000000"; -- 0
                reset <= '1';
            else
                hex6    <= "1111001"; -- 1
            end if;
    end process;

but the key is still not toggling properly. If I change key(0) detection to rising edge

(key(0) = '1' and key(0)'event)

the key shouldn't be working from my opinion. But it is the same inproper toggling. What am I missing ?

Thanks for reply.