Merge lp://staging/~tcross/vm/605799 into lp://staging/vm

A partial fix for bug 605799.

The problem looks like it is due to a bug in emacs force-mode-line-update. For some reason, when you select Help -> Swith to Emacs Menubar, the menu is not updated immediately (which should occur due to the call to vm-menu-set-menubar-ditry-flag. However, putting a (message "") into the function prior to the call to force-mode-line-update appears to work and the menu bar gets updated.

Without this, the menu bar does not get updated unless some other event occurs i.e. mouse click, move cursor or even wait until something else occurs (maybe gc?). I think it will be necessary to instrument some of the emacs functions and/or run under gdb to really see what is going on. Will raise it on emacs-dev to see if I can get some advice.

Interestingly, the menu pdate delay/problem does not appear to affect the new VM -> Switch to VM Menubar menu, which works without the dummy 'message' line. So, the problem could be due to the way the Help -> Switch to Emacs Menubar is installed. There are a number of other menu related bugs to fix and there is some 'old/moldy' code (even some emacs 19 specific stuff), which I think I might try and clean-up and see if that improves things. This may take a while.

As the 'fix' is really a bit of a kludge, you may not want to merge it. However, I think it is an improvement over what is currently there. At the very least, it would be good if you could try out the changes under Windows and see if it fixes the issue there as well.