Computer is not set to Do Not Disturb but Display Text Briefly does nothing.
Replace but (in your sentence) with therefore
( as @iampariah explains, Do Not Disturb switches off brief notifications, but allows KM display text in window actions )
Is the same true for all KM "Display Text Briefly"s? Have you allowed Notifications from KM? Check System Settings->Notifications->Application Notifications and make sure that both KM and KM Engine are allowed and set to at least show Banners.
Yes, Display Text Briefly does not work at all. Notifications were indeed off; however, turning them on has has the desired effect.
Correction KM Engine was also off, with both on, it works as expected. Thanks very much for your help!
2 Likes
@ComplexPoint In the interests of keeping the forums friendly, especially to people for whom English is not their first or primary language, maybe we should focus less on correcting grammar when the point comes across just fine with colloquial language.
Not remotely interested in grammar 
My point was that switching on Do No Disturb disables (rather than enabling) notifications.
( perhaps a misunderstanding )
1 Like