Upgraded to 19.04 - System Freezing when Opening Activities Menu

This was caused by a gnome extension workspace grid. Removed extension and solved issue. When viewing system logs was seeing message like this:

Apr 20 21:07:31 name gnome-shell[2382]: JS ERROR: TypeError: child is null#012getNonExpandedWidth@resource:///org/gnome/shell/ui/overviewControls.js:282:9#012_updateWorkspacesGeometry@resource:///org/gnome/shell/ui/overviewControls.js:448:31#012vfunc_allocate@resource:///org/gnome/shell/ui/overviewControls.js:391:9#012_updateSwitchUserSubMenu@resource:///org/gnome/shell/ui/status/system.js:167:9
Apr 20 21:07:31 name gnome-shell[2382]: JS ERROR: TypeError: child is null#012getNonExpandedWidth@resource:///org/gnome/shell/ui/overviewControls.js:282:9#012_updateWorkspacesGeometry@resource:///org/gnome/shell/ui/overviewControls.js:448:31#012vfunc_allocate@resource:///org/gnome/shell/ui/overviewControls.js:391:9

To escape this situation, you can also press Alt+F2, type r and press Enter. This restarts Gnome, but it is a gentle and fast restart, your apps remain open.