Not clear which non-widget data types get expanded and which don't


In this example, `Theme` has a `ThemeData`. It's not clear to me whether there's just a whitelisted handpicked set of "data" types that expands into its constituents and why `ThemeData` is opaque but `TextStyle` under `actionTextStyle` is expandable.

Also a bit inconsistent that `Theme` has an opaque `ThemeData` (which follows the real tree composition) but the `CupertinoTheme`'s `CupertinoThemeData` is somehow inlined into the `CupertinoTheme` node directly. Same with the `IconTheme` where the `IconThemeData` is inlined.

Start by locating the widget inspector code that decides how object and data nodes are expanded. Compare the handling of ThemeData, TextStyle, CupertinoThemeData, and IconThemeData against the behavior shown in the issue. Done should clarify the expansion rule and explain or resolve the inconsistent treatment.

Vom Indexierungsmodell aus dem Issue-Text verfasst.