How to eliminate rogue keybinding?

[dapfy]

To access my 10 virtual desktops, I do the following:

for i in 1 2 3 4 5 6 7 8 9 10; do
	dconf write /org/gnome/desktop/wm/keybindings/switch-to-workspace-$i "['<Super>${i: -1}']"
	dconf write /org/gnome/desktop/wm/keybindings/move-to-workspace-$i "['<Alt><Super>${i: -1}']"
done

On inspection, these settings are still successful.

However, since 19.04, the combinations with 7, 8 & 9 no longer have any effect. <Super>7 instead pops up an annoying help window. I can't find where that overriding key binding comes from.

[TheFu]

Pick a different GUI? There are about 50 choices.