Linux native menu
In IntelliJ IDEA for Linux, you can use the global main menu similar to macOS – a horizontal menu attached to the top of the screen. By default, this menu is enabled, although not all Linux desktop environments support it natively.
Disable the native menu
Press Control+Shift+A to open the Find Action dialog, then type
Experimental features, and press Enter.
Clear the checkbox next to the linux.native.menu item, apply the changes, and close the dialog.
Restart IntelliJ IDEA.
The native menu might not display on some desktop environments. If you have followed the steps described on this page, but the menu doesn't appear, try installing JavaFX Runtime for Plugins from JetBrains Marketplace.