The external monitor support in Mavericks is much improved, as we noted in yesterday’s tip on getting the Dock to show up on your second monitor.
The menu bar itself will dim when you’re not actively on a specific monitor, as well. In other words, if you’re using monitor A, the menu bar will look opaque, as per usual, while it will dim and go see-through on monitor B. When you switch your active focus by using the cursor on monitor B, though, the menu bar will brighten and not let you see through it, while the menubar on monitor A will go semi-transparent and dim.
There is a way, however, to just hide the menu bar altogether on your secondary monitor, if that’s how you want things to work. The preference is in an unintuitive place, though.
Launch System Preferences with a double click in the Applications folder, one click in the Dock, or select it from the Apple Menu.
Click on the Mission Control preference pane icon and, once it’s in front of you, uncheck the box next to “Displays have separate Spaces.” This entirely non-sequitor check box will keep the menu bar from showing up on the secondary monitor.
If you want it back, just re-check the box. You’ll need to log out and log in each time you do these steps to see the changes. Unchecking this box will also mess with how Mavericks deals with full-screen apps on the secondary monitor, so if you don’t like how it ends up, put things back the way they were and just deal with the translucent menu bar.
Via: OS X Daily.