This is my first post.
This is a way to hide wow in the toolbar, by simply pressing F9 to hide it, and F10 to show it. 
In this guide I used AutoIT.
Step 1: First you need AutoIT, which is free. AutoIt v3 - Downloads
Step 2: After you installed the program, open notepad.
Copy this into notepad:
Code:
hotkeyset ("{F9}", "hide")
hotkeyset ("{F10}", "show")
func hide()
WinSetState ( "World of Warcraft", "", @SW_MINIMIZE )
WinSetState ( "World of Warcraft", "", @SW_HIDE )
endfunc
func show()
Winsetstate ( "World of Warcraft", "", @SW_SHOW )
WinSetState ( "World of Warcraft", "", @SW_MAXIMIZE )
endfunc
while 1
sleep(1000)
WEnd
Step 3: And save it like this

Just name it like you want, but remember that it needs to end with .au3
Step 4: Just run the script and you can hide it, and nobody knows that are playing wow, unless they are looking in taskmgr.exe