crash on winMenuAddItem (PR#8961)

Full_Name: Thomas Ruf
Version: 2.3.1
OS: Windows XP home
Submission from: (NULL) (193.154.219.1)

Having created a large Menu with many submenus, R crashed (with an error message
from Windows) when adding another submenu using winMenuAddItem. The problems
seems to be caused by a limit on the number of submenus that can be created?

I can reproduce this behavior by creating the following (nonsense) menu:

winMenuAdd ("Data")
winMenuAddItem ("Data/Read", "Text", "none")
winMenuAddItem ("Data/Read/Text 0", "Load File 0", "none")

n<-30
for (i in 1:n){
item= paste("Data/Read/Text",as.character(i) )
subitem=paste( "Load File",as.character(i))
winMenuAddItem(item, subitem, "none")
}

With n<-10, the menu is created and R continues to work just fine. With n<-30,
however, my RGui reliably crashes, and with n<-18, it crashes about half of the
time.

The are no warnings or error messages from R prior to the crash. 

Best,
Thomas