I'm running Ubuntu 18.04 with all updates and the default Gnome desktop environment.

When I click the 'Show Applications' icon (the square of nine dots) at the left end of the panel which I have set at the bottom of the screen, the window opens up correctly but, while it is set for 'All', the icons, in unison, give a little twitch at regular intervals. When I set the screen to 'Frequent', the icons of my frequently used applications remain stable. In all other respects 'Show Applications' works with no problems. Is this twitching I have noticed when all applications are showing normal behaviour? If so, is there a setting I can modify to stop it or if not, what is the likely cause?