When i right click on file /class1.php in project root and select Find Usages... it showed none even though there is "/includes/class1.php"
When i try to delete and selected "usage search" it found 5 usages. However this usages was of file with same name that is in "includes" folder ("/includes/class1.php") and i tried to delete "/class1.php".
On other hand "find usages" cannot find usage of "config.php" if its included like this:
include_once _MAINSITEPATH_ . "config.php";
Have to use Ctrl+Shift+F to find in math only thing working for sure.