Function refresh_problems_view 

pub fn refresh_problems_view(
    activator: &mut dyn ModeActivator,
    view_id: BufferId,
    entries: &[ErrorEntry],
) -> Option<usize>

RV.3 (2026-08-10): rebuild an existing *problems* view from the current error list, in place. Returns the new entry count, or None when the view is unknown to the multibuffer registry or the fresh entry set yields nothing to show (in which case the view is left exactly as it was — a refresh must never blank the buffer the user is reading).

In place is the whole point: create_problems_view mints a new BufferId every call, so “refresh” cannot be a re-open without stranding the old view and opening a second *problems*. crate::MultibufferDocumentHandle::replace_excerpts swaps the source map and excerpt list atomically and republishes, so the buffer the user is looking at simply becomes current.

Sources are re-read from disk, which is the point of a refresh here: the view’s sources are freshly-spawned handles taken at open time, not the live editor buffers, so both the error list and the file contents may have moved on.