Okay, I’ve reproduced this problem here and have documented it for resolution.
There is a workaround. It is possible to specify the font for each of the selectors in the dialog through other means – this dialog is a convenience:
Text Editor Code and Debugger, Editor Characters: open the Code view of the Layout tab. From the View menu, select Code Font or Character Font respectively. I have verified that Noto Sans Adlam appears in these menus.
On Screen Keyboard: open the Code view of the On-Screen tab. Change fontname attribute of the <encoding> element.
Touch Layout: open the Code view of the Touch Layout tab. Change the font property for each form factor in use (phone and/or tablet – desktop is not currently used).
Thanks, that works.Actually you can specify the desired font for the layout view in either Design or Code view, and what you choose for Character font applies to both views.