If non-existent key files are in Pageant's registry path, they can't be removed easily

[ghost]

If key filenames have been persisted to the registry, they can't be removed easily. This results in:

a number of times during startup.

Perhaps there should be a way to clear this path from the UI, or a way to save the setting to a file instead?

[FauxFaux]

You should now get:

---------------------------
Pageant
---------------------------
Couldn't load 'non-existent-file.ppk': Couldn't load this key (unable to open file)

Would you like to remove it from the list of automatically loaded keys?
---------------------------
Yes   No   Cancel   
---------------------------

... for each broken key, where:
Yes: Remove the key from the registry.
No: Do nothing to this key.
Cancel: Do nothing and don't bother trying to load any other keys.