always open datasource panel initially if connection & fix styles

[Light2Dark]

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🔍 Description of Changes

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• For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
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Project	Deployment	Review	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jan 7, 2026 7:15pm

[manzt]

I like the goal here of making datasources more visible when they're relevant.

One thought on the state persistence: the hasUserInteracted flag being persisted means once a user collapses the panel, it won't ever auto-open again, right? Even in future sessions with new connections?

One idea I had was to keep open sections persistent but reset interaction tracking each session:

const openSectionsAtom = atomWithStorage<OpenSections[]>(
  "marimo:session-panel:open-sections",
  ["variables"],
  jotaiJsonStorage,
);

const hasUserInteractedAtom = atom(false); // resets each session

Another would be to maybe do something "smarter" and try to auto-open when new connections appear. But I'm guessing there would be some false positives with this:

interface SessionPanelState {
  openSections: OpenSections[];
  lastSeenConnectionCount: number;
}

// then auto-open if datasourcesCount > state.lastSeenConnectionCount

Neither is blocking, just wanted to flag some more ideas.

[manzt]

Idk if relevant anywhere, but this would make this constant readonly.

Suggested change

	};
	} as const;

[Light2Dark]

I like the goal here of making datasources more visible when they're relevant.

One thought on the state persistence: the hasUserInteracted flag being persisted means once a user collapses the panel, it won't ever auto-open again, right? Even in future sessions with new connections?

One idea I had was to keep open sections persistent but reset interaction tracking each session:

const openSectionsAtom = atomWithStorage<OpenSections[]>(
  "marimo:session-panel:open-sections",
  ["variables"],
  jotaiJsonStorage,
);

const hasUserInteractedAtom = atom(false); // resets each session

Thanks! I like this idea and a simpler default.