I have installed your last version 0.1.5 successfully but :
1) I receive the following error message:
Notice: Use of undefined constant WPWM_LIB - assumed 'WPWM_LIB' in /homez.792/mrfosses/www/mr-fosses-2-tst/wp-content/plugins/wp-welcome-message/wp-welcome-message.php on line 97
I have changed the line 97 to 'WPWM_LIB'
2) When I enable the 'Only For Fist Time Visit' option, the Welcome message don't never displayed. Not displayed also after disable the welcome message or close/open a new navigation session.
I use Google Chrome as navigator and Static page as Home page.
3) Why your plugin don't use the WP-Setting menu but a new item ijn the WP-Menu admin