Thanks for the quick reply, shamim.

So, just a couple more quick questions:

– Should the complete plugin still be installed in /wp-test/wp-content/plugins/ (so that it can be used with any installed theme)?

– Should /wp-test/wp-content/themes/spacious-child/front-end-pm/ only contain “viewmessage.php” (and any other files to be changed in the child them only) without all of the other subfolders, etc?