Only Menu Solutions are left blank in the WordPress website background

Sometimes, after the WordPress system is migrated, or after apache or php is moved, the background menu is found, but when you click it, the right form is not loaded, and the content is blank. The plug-in menu can be clicked and the operation is normal. The tragedy is like the figure below:
Wordpress background not loaded

 

You may also find the following error message:

Fatal error: Access to undeclared static property: WP_Screen ::$ this
In blog/wp-admin/shortdes/screen. php on line 706

You are really sure you haven't moved any WordPress configuration! How can this problem be solved? Don't be careful. Someone in stackoverflow has the same problem. Find the following file

/Wp-admin/shortdes/screen. php

Open it in your favorite text editor, and then

_ Help_sidebar;?> (Note that the number of spaces may be slightly different)
Replace
_ Help_sidebar;?>

After saving it, check whether it is OK?