You also see a right-pointing double arrow which, when you click it, shows the missing menus.
Do one of the following
Restart your computer. The changes take effect once Windows has restarted.
If the DPI Scaling in Windows is greater than the default of 96 dpi, the menus in the Elements Organizer become too large to display.
The list of system requirements for Photoshop Elements and Adobe Premiere Elements both state that 96 dpi is required.
However, on some systems, a custom setting of up to 120% or 115 dpi works without making the menus disappear.