The patch below replaces a use of `eval` with `apply`, but along the way
I wondered about some of the details of `org-eval-in-calendar` (see the
FIXMEs), the most important of them being: why doesn't it use
`with-selected-window`?

Assuming the change from `eval` to `apply` is OK, I'll upgrade my patch
with an appropriate commit message, but I'd first like to understand
better what's at stake.


        Stefan