If you run fullscreen Wine games or apps and the Unity panel and launcher show up on top of the game/app in some cases, here's a simple fix you can use.
I don't play too many games (especially Wine games) so I'm not sure how many are affected by this, but I've encountered this issue with World of Warcraft (via Wine) and I though the workaround below might help some of you, especially those who are relatively new to Ubuntu.
To fix Unity panel and launcher being displayed on top of some fullscreen Wine games/applications, firstly install CompizConfig Settings Manager (CCSM):
sudo apt-get install compizconfig-settings-manager
Then open CompizConfig Settings Manager, search for the "Workarounds" plugin (it should be displayed under "Utility") and enable "Legacy Fullscreen Support":
There is another way to solve this: by setting Wine to Emulate a virtual desktop (Wine configuration > Graphics) but that workaround has some drawbacks, like displaying a background for non-maximized Wine apps, that's why using the CCSM settings mentioned above should provide a better results.