Breadcrumbs

Use lcsBreadcrumbs wherever people go more than one level deep: a project, then its phase, then a task; a folder tree; a category, then a product. Canvas apps have no breadcrumb control, and the usual substitute is a label with the path in it, which can't be selected, isn't announced as navigation, and grows past the screen's edge on the fifth level. This component is the trail done properly:

• Levels from a table of Key and Label, root first; the last row is where the person is now;
• Every level but the current one is a real button, named "Projects, level 2 of 4" for a screen reader; the current level reads "current page";
• Long trails collapse: past MaxVisible levels, the middle folds behind a "…" button that reads "Show all 6 levels";
• OnNavigate(Key, Label, Level) when a level is selected, GoUp() for a Back button, CurrentLabel and ParentKey for the rest of the screen;
• A chevron between levels, or any text you give SeparatorText; an optional home icon; your accent colour on the levels you can select.

The examples call it bcPath on a screen that shows one project's tasks.

Keep the trail in a variable your screens extend and shorten:

// Screen.OnVisible, arriving at a project's tasks
Set(varPath, Table({Key: "home", Label: "Home"}, {Key: "projects", Label: "Projects"}, {Key: varProject.ID, Label: varProject.Name}, {Key: "tasks", Label: "Tasks"}))

// bcPath.Items
varPath

Go to the level that was selected, and cut the trail there:

// bcPath.OnNavigate
Set(varPath, FirstN(varPath, Level));
Switch(
    Level,
    1, Navigate(scrHome),
    2, Navigate(scrProjects),
    3, Navigate(scrProject, ScreenTransition.None, {ID: Key})
)

A Back button that goes one level up, and the screen's title from the trail:

// btnBack.OnSelect
bcPath.GoUp()

// lblTitle.Text
bcPath.CurrentLabel

Show every level of a long trail from a link elsewhere on the screen:

// lnkShowAll.OnSelect
bcPath.ShowAll()

• Columns. Items wants exactly Key and Label. From a Dataverse table, build the rows with ShowColumns and RenameColumns, or write them out as in Use it, which is usually clearer because each level comes from a different screen.
• A parent lookup. A self-referencing table (a category with a parent category) gives you the trail by walking up: LookUp(Categories, Category = varCurrent.'Parent category'.Category) for the parent, and again for the grandparent. Power Fx has no loop, so write the walk for the depth your data has (three or four levels is the usual limit of good design anyway), and give each row the record's GUID as its Key.
• Keys for Navigate. Put the record's GUID in Key so OnNavigate can open the record's screen with LookUp and no second query for the name.

• The trail is a group named "Breadcrumb". Each level you can select is a button whose name is its label plus "level n of N"; the current level is text that reads "current page", unless CurrentIsLink makes it selectable too. The Show all button reads how many levels it reveals.
• Tab moves between the levels; Enter and Space select one. Separators and the home icon are decorative and skipped.
• The current level sits in a tinted pill and is bold as well as a different colour, and it's named "current page", so state is never colour alone.
• With Motion on, the current level's pill pops in when the trail changes, in under a third of a second. None plays for people who've asked their device for reduced motion, and Motion off shows it at once.

• Each level is as wide as its label, worked out from its length and Size (Power Apps can't measure text), so a label with many wide or narrow letters can sit a little loose or tight. MaxLevelWidth caps a level: a longer label is cut, and the full label stays in the tooltip and the accessible name. Set Width to hold the levels you show.
• At most eight levels show at a time; a longer trail always folds its middle behind Show all.
• Collapsing keeps the first level and the last MaxVisible - 1; the hidden levels come back with Show all, ShowAll(), or when the trail shortens below MaxVisible. A reset collapses it again.
• The component doesn't navigate by itself: OnNavigate tells your app which level was chosen, and your app shortens the trail and changes screen, so the trail is always what your app says it is.

• 0.1.0: first version: levels from a table, buttons named with their level, Show all for long trails, chevron or text separators, the home icon, OnNavigate, GoUp, ShowAll, Collapse, the outputs, light and dark, the current level's pill.