Why all of a sudden can I not see my taskbar in Win 7 when I have a Chrome window open, but if I open up other programs it doesn't hide the taskbar? Why is this Chrome specific?

UPDATE: I've auto-hide the task bar now and so now I can bump the taskbar when Chrome is maximised so should be sorted.
Still if I chose to stop auto-hide of the task bar it totally disappears in Chrome only as if I'd chosen to have Chrome fullscreen when in fact it's only maximised.
It has also for some reason decided to stop showing onscreen notifications when I increase/decrease the volume, turn on Caps or Num Lock (I don't have lights on my laptop informing me if these are on off, I only get little images on the screen whenever they are changed. I could do with the volume and Locks notifications back.
Anyone?