Like the AJAX implementation and the basic functionality. Found/fixed two bugs and extended functionality to include future dates.
Bug 1 - list mode did not filter for the category selected
Bug 2 - after initial display, dates with posts were not hightlighted (while navigating months, for example).
Both straightforward to fix.
Added future posts to display - simple extension.
Thanks to author for the heavy lifting - I just did a little patching and will continue to use this plugin.