vm-virtual-update-folders giving error

[Uday Reddy]

Doing update for loaded virtual folders, after newly visiting the base folder, is giving this error:

Debugger entered: (vm-thread-root-null nil)
  apply(debug vm-thread-root-null nil)
  vm-thread-root(nil)
  vm-thread-root-p(nil)
  vm-select-operable-messages(1 t "Update")
  vm-virtual-update-folders(1)
  call-interactively(vm-virtual-update-folders nil nil)

[Uday Reddy (reddyuday)]

Actually, it is not clear what vm-virtual-update-folders is supposed to do.

More investigation needed.