Struct PaneRenderProvider 

pub struct PaneRenderProvider {
    pub render: Option<PaneRenderFn>,
    pub status: PaneStatusFn,
}

One mode’s pane-render contribution. Kept paired so a mode owns both its content rendering and its status label – the two are almost always defined together (a help pane wants [help] in the status; a file-tree pane wants [tree] /path/to/root).

Fields

render: Option<PaneRenderFn>

How to paint the pane’s content, or None when the mode’s buffers paint through the shared document compose path.

DL.4: None is the goal state, not a special case. A mode that supplies its own painter re-implements scroll windowing, the cursor row and per-row styling — which is how one arithmetic slip came to live in four places (CV.5). The file tree became None when it converged to a DocumentEntry; oil follows in DL.5.

status: PaneStatusFn