Shell Collections

Shell Collections

A shell collection is a collection that has no media directory and no launcher of its own — it exists purely to group other collections under a named heading. Think of it as a folder for your collections, the same way a Collection is a folder for items.

The name comes from the shape: a shell is a frame with no contents of its own. You give it children, and the children carry the launchers and media.

When to use one

Shell collections shine when you have a library that splits naturally into a few high-level categories, each containing several "real" collections:

Video (shell)
├── Films               (mpv)
├── TV Shows            (mpv, --no-resume-playback)
└── Documentaries       (mpv)

Audio (shell)
├── Albums              (mpv --no-video)
├── Audiobooks          (mpv --no-video --save-position-on-quit)
└── Podcasts            (mpv --no-video)

Reference (shell)
├── Manuals             (xdg-open, .pdf)
├── Cheat Sheets        (xdg-open, .pdf)
└── Reports             (xdg-open, .pdf)

Each shell renders at the root of the sidebar tree as a tile that opens its children on Enter. The shell itself never tries to scan a media directory or hand anything to a launcher — everything happens one level down, in the leaf collections it contains.

When not to use one

If your goal is just to filter the visible set of collections by a tag like genre or category, the collection type field on each collection plus the type filter is usually a better fit — it preserves a flat sidebar and lets a single collection appear in multiple categorical views.

Reach for a shell when you want the navigation to mirror the hierarchy: when a user opens "Video" they see Films / TV Shows / Documentaries as tiles, not the union of every video in the library.

Creating one

1. Open the Settings Dialog with Ctrl + , and click Add Collection.
2. On the Basic tab, give it a name (e.g. Video).
3. Skip the Paths & Extensions and Launcher tabs entirely — leave everything blank.
4. Drag your existing collections under it in the tree on the left, or set their Parent Collection field to the shell's name.

That's it. Kartend's validator emits a soft warning ("no media directory specified") on a collection without media, but it suppresses that warning the moment the collection has at least one child — the validator treats parent-only collections as legal first-class citizens.

Where to find this — Settings Dialog → tabs Basic, Sidebar, Appearance, Colors.

INI form

A shell collection looks like any other in kartend.cfg — the absence of mediaDirectory and launcherPath is what makes it a shell:

[Video]
name=Video
type=Video
collectionIcon=~/Pictures/icons/video.png

[Video > Films]
name=Films
parentCollectionIndex=0
mediaDirectory=~/Videos/Films
launcherPath=/usr/bin/mpv
launchParameters=--fullscreen
extensions=mkv,mp4,avi,webm

[Video > TV Shows]
name=TV Shows
parentCollectionIndex=0
mediaDirectory=~/Videos/TV
launcherPath=/usr/bin/mpv
launchParameters=--fullscreen --no-resume-playback
extensions=mkv,mp4,avi

Subcollections reference their parent by index (parentCollectionIndex) which Kartend normalizes against the section list at load — re-ordering collections in the dialog rewrites these automatically.

What a shell collection can still have

Even without media, a shell collection still owns the per-collection appearance fields. Useful ones in this context:

Field	What it does
Type	Tags the shell for the type filter. Children inherit nothing — set their own type if you want them to appear under the same filter.
Collection Icon	The image painted on the shell's tile (icon column of List view, tile in Grid). Children paint their own icons inside the shell once you open it.
Header Logo	Logo at the top of the shell's grid (visible when you've drilled in).
Background	Per-collection background color / image / video — the shell's grid honours this even though it contains no media.
Grid Width / Tile Size / Spacing	Layout knobs that govern how the children's tiles render when the shell is open.

What a shell collection cannot have:

• A media directory — by definition. Adding one promotes it from shell to a leaf collection, and items would start appearing alongside the child tiles. Kartend permits this but it's almost never what you want.
• A launcher — there's no item-level launch path through a shell. Enter on a shell tile opens its children, not a launcher.
• A working Show All Subcollection Items toggle — the toggle exists on every collection, but on a shell it has nothing to flatten upward into.

Nesting shells

Shells can contain other shells. The depth limit is whatever the parent-cycle check permits (currently MAX_HIERARCHY_DEPTH = 32 levels). In practice, two levels covers almost every library:

Library (shell, root)
├── Video (shell)
│   ├── Films
│   └── TV Shows
├── Audio (shell)
│   ├── Albums
│   └── Audiobooks
└── Reference (shell)
    ├── Manuals
    └── Cheat Sheets

A single top-level wrapper shell like Library above is more useful than it might first appear. The tile area always shows whichever collection is currently active, so wrapping every category under one root shell gives you a tile-based home view: the wrapper becomes the canonical landing surface, with each category showing up as a tile you can navigate into and Back out of.

Set the wrapper as your startupCollection (Settings → General, or INI: [General] startupCollection=Library) and Kartend boots straight into the home view.

If you'd rather not maintain a wrapper collection at all, the same landing experience is available built-in: enable Settings → General → Use Home View ([General] useHomeView=true). Kartend boots into a synthetic tile grid containing one tile per root collection, and Back from any root-level collection returns there. The wrapper-shell pattern remains useful when you want a real collection at the top with its own appearance overrides (background, header logo, layout knobs); the built-in Home view is preferable when you want zero collection bookkeeping.

Alias parents and shells

A shell collection can be the alias parent of a collection that already lives elsewhere — useful when one collection naturally belongs in two categories. Example: a Concerts collection lives under Video, but you alias-parent it under Audio too so it shows up in both shells without duplicating the media.

The aliasing is one-way: changes to the aliased collection (rename, reparent, delete) reflect in both places, and removing the alias parent only severs the link, not the original.

Quick reference

Question	Answer
Do shells appear in search results?	The shell itself doesn't (it has no items), but its children's items do via recursive subcollection search.
Do shells appear in launch history?	No — there's nothing to launch.
Do shells appear in the Statistics dialog?	The aggregate row sums their descendants. The shell row itself shows zero plays.
Do shells survive .kart export?	Yes — exporting a shell exports its descendants too. See Backup & Sharing.
Can I make a shell the startup collection?	Yes — startupCollection=Video is valid; Kartend opens that shell on launch and you navigate down with Enter.