yes, i had these problems after the latest pi os update also. but they are slowly gettig solved. the fastest way for me was to logout from the x system and login again with user pi and your password, this is faster as restarting the pi.
after this the whole screen is usable for the apps.
holger
# eventually an delay for the x-system after rebooting will also be an solution to give the apps an complete initalized x-window system.
after this the whole screen is usable for the apps.
holger
# eventually an delay for the x-system after rebooting will also be an solution to give the apps an complete initalized x-window system.