I added the US layout to my three layouts and Onboard showed the correct layout, even after restarting the computer.
Then I removed the US layout from my layouts lists in the keyboard settings pane of the System Settings and Onboard continued to show the correct layout.
Afterwards I clicked on the "Restore to Defaults" button, and restarted the computer. Onboard showed again the US layout, even if it was not in the list with my layouts.
I added the US layout to my three layouts and Onboard showed the correct layout, even after restarting the computer.
Then I removed the US layout from my layouts lists in the keyboard settings pane of the System Settings and Onboard continued to show the correct layout.
Afterwards I clicked on the "Restore to Defaults" button, and restarted the computer. Onboard showed again the US layout, even if it was not in the list with my layouts.