Thank you @Silicio for your confirmation.
So the printscreen trick works for the FF3 and GS290.
Unfortunately I noticed that is not a permanent solution. App Lounge stopped to work 3 times for me today, but each time I solved with the swipe from right to left.
Moreover I had to repeat this 2or 3 times (swipe, try to start App Lounge, swipe,…)
So it is a temporary workaround until an official fix will be released.
And I have Signal installed, as read in @peter post