- Edited
Please be aware that the "Show Popup" feature does not work anymore in Android 10!
Why?
Android 10 and higher place restrictions on when apps can start activities (the popup is an activity) when the app is running in the background.
These restrictions help minimize interruptions for the user and keep the user more in control of what's shown on their screen.
COL Reminder shows the notification and also starts an activity, the Popup Dialog, but the main app isn't visible/in foreground at this time.
This is now not allowed anymore.
Solution?
With version 3.6.3 there is now a new setting called "High Priority with Popup" on Android 10.
It's not exactly the same as the "Show Popup" but I think a good alternative and in some cases the better solution I think.
If the screen is on you see a "Heads Up" notification.
A "Heads Up" notification will stay on the screen at the top until you swipe it up. So you want miss a reminder if you are currently using the phone.
If the screen is off the phone will be automatically turned on and you see the popup again.
But be aware that the system choose to display either a heads-up notification or the popup.
But in most cases it should be as described above.
See the info on the official docs from Google: