Q: Wifi is not auto connect after resume from sleep

I keep my Mac Book Pro up-to-date with software updates.

I recently update to OS X 10.8.3 (12D78).

Since then when I open my laptop after closing it and put it to sleep the wifi connection does not re-connect automatically.

I have to click on the wifi sign near the clock and select the network to connect to.

How can I make it connect automatically like it used to?