I am trying to modify the icons in the left hand side gallery in the powerapps training for office template.

in the App OnStart property the code is:
Concurrent(
Set(
StepsPanelCodeFontSize,
10
),
Set(
_selectedTutorial,
{
Row: 1,
Title: "About",
Image: HomeIcon
}
),
ClearCollect(
NavigationMenu,
{
Row: 1,
Title: "About",
Image: HomeIcon
},
{
Row: 2,
Title: "People picker",
Image: PeopleIcon
},
{
Row: 3,
Title: "Planner",
Image: PlannerLogo
},
{
Row: 4,
Title: "Outlook",
Image: OutlookLogo16
},
{
Row: 5,
Title: "OneNote",
Image: OneNoteLogo16
},
{
Row: 6,
Title: "Pop-up lightbox",
Image: PopUpIcon
}
)
)
I change Image PeopleIcon to HomeIcon and this is the result:

I have no idea why all icons and labels disappear.
I have also changed the OnSelect property of the PeoplePickerScreen to match the HomeIcon, but still no change.
Set(
_selectedTutorial,
{
Row: 2,
Title: "People picker",
Image: HomeIcon
}
)
Can anyone help me understand what is going on?