Cannot use the greek keyboard in Ubuntu

I installed the Keyman software and the greek keyboard within, I can see it Keyman Configuration, is listed there the Polytonic Greek (SIL) 1.5. I also see the Onboard keyboard, but this one is showing the active keyboard I select from the Ubuntu Keyboard settings. How can I use the Keyman keyboard? All applications use the installed system keyboards. I don’t have this problem in Windows.

Thank you.

Hi there

Please see the additional steps in the section “Install the Input Source in Region & Language Settings
https://help.keyman.com/products/linux/13.0/guide/installing-keyboard

This will be fixed by Pull request 3278 when Keyman for Linux 14.0 is released.