[Bug Fix] dont get premissions on plugin installation

Hi everybody!
sorry if i have some language mistakes, i dont know english so good.
ok so, here is my fix to one of the most common wordpress bugs, when trying to install new plugin everythings goes perfect, but!
when trying to go to the admin of the plugin only the main page is working good but all the inner pages( sub pages ) get an error message:
“You do not have sufficient permissions to access this page.”
This is because wordpress thinks that this page doesnt exists, the fix is very easy:
go to file:

{ROOT}/wp-admin/includes/plugin.php

find( near line 1390 ):
} elseif ( $submenu_array[2] == $pagenow && empty($typenow) && ( empty($parent_file) || false === strpos($parent_file, '?') ) ) {
and replace with:
} elseif ( $submenu_array[2] == $plugin_page && empty($typenow) && ( empty($parent_file) || false === strpos($parent_file, '?') ) ) {
this withh check if the page is in the plugin and let you premissions to get into it, enjoy :-)!