diff --git a/components/reasoning-workspace.jsx b/components/reasoning-workspace.jsx
index 449f85b..28252d8 100644
--- a/components/reasoning-workspace.jsx
+++ b/components/reasoning-workspace.jsx
@@ -527,6 +527,14 @@ export default function ReasoningWorkspace({
   const pendingTurnRef = useRef(null);
   // ── Experiment 12: toggle between progress panel versions (temporary experimental UI) ──
   const [panelVariant, setPanelVariant] = useState("c");
+
+  // ── RTO.01 — presentation-only selection for open investigation items ──
+  const [selectedPresentationItemId, setSelectedPresentationItemId] = useState(null);
+
+  // ── RTO.02 — case / question workspace lifecycle (presentation only) ──
+  const [focusedPresentationItemId, setFocusedPresentationItemId] = useState(null);
+  const [doneForNowIds, setDoneForNowIds] = useState([]);
+
   const { saveSession, loadSession } = useSessionPersistence();
 
   // Persist workspace state on every successful update (Phase 3)
@@ -663,49 +671,185 @@ export default function ReasoningWorkspace({
             <div className="grid grid-cols-1 gap-6 lg:grid-cols-3">
               {/* ── Left lane: active conversation & notebook ───────── */}
               <div className="space-y-6 lg:col-span-2">
-                {/* Active question — only when there is one */}
-                {hasSelectedQuestion && (
-                  <>
-                    <CurrentInvestigationCard selectedQuestion={selectedQ} graph={graph} />
+                {/* ── Open questions (case workspace) — no ranking bias ── */}
+                {(() => {
+                  const openNodes = graph.nodes.filter(
+                    (n) => n.kind === "unknown" && n.status !== "resolved" && !doneForNowIds.includes(n.id)
+                  );
+                  if (openNodes.length <= 1) return null;
 
-                    {updateStatus === "success" && !isUpdating && (
-                      <UpdateAcknowledgement updateResult={result} />
-                    )}
-                  </>
-                )}
+                  return (
+                    <div className="space-y-4">
+                      <h2 className="text-[11px] font-medium tracking-widest uppercase text-gray-300">
+                        Open questions
+                      </h2>
+                      <div className="space-y-1">
+                        {openNodes.map((node) => {
+                          const isSelected = selectedPresentationItemId === node.id;
 
-                {/* Answer form — only when a question is active and not loading */}
-                {!isUpdating && canAnswer && (
-                  <form onSubmit={handleUpdateCaptureAndSubmit} className="space-y-4 rounded-lg border border-gray-200 bg-white p-5">
-                    <div>
-                      <label htmlFor="rw-answer" className="mb-2 block text-sm font-medium text-gray-700">
-                        Response
-                      </label>
-                      <textarea
-                        id="rw-answer"
-                        value={answer}
-                        onChange={(e) => setAnswer(e.target.value)}
-                        rows={4}
-                        disabled={updateStatus === "loading"}
-                        data-testid="response-textarea"
-                        className="w-full rounded-lg border border-gray-300 px-4 py-3 text-sm focus:border-gray-500 focus:outline-none focus:ring-2 focus:ring-gray-400 disabled:cursor-not-allowed disabled:opacity-60"
-                        placeholder="What do you know about this?"
-                      />
+                          return (
+                            <div key={node.id}>
+                              <div
+                                onClick={() => {
+                                  if (result?.selectedQuestion?.nodeId !== node.id) {
+                                    setSelectedPresentationItemId(
+                                      selectedPresentationItemId === node.id
+                                        ? null
+                                        : node.id,
+                                    );
+                                  }
+                                }}
+                                style={{ cursor: "pointer" }}
+                                className={`w-full text-left rounded-lg px-4 py-3 transition ${
+                                  isSelected
+                                    ? "border border-gray-300 bg-gray-50/60"
+                                    : "hover:bg-gray-50"
+                                }`}
+                              >
+                                <p className={
+                                  isSelected
+                                    ? "text-sm font-medium text-gray-900 leading-snug"
+                                    : "text-sm text-gray-700 leading-snug"
+                                }>
+                                  {node.label}
+                                </p>
+                              </div>
+
+                              {isSelected && (
+                                <div className="px-4 pb-4 pt-1 space-y-3">
+                                  <p className="text-sm leading-relaxed text-gray-500">
+                                    We have not explored this yet. Do you want to work through it?
+                                  </p>
+                                  <button
+                                    onClick={() => {
+                                      setSelectedPresentationItemId(null);
+                                      setFocusedPresentationItemId(node.id);
+                                    }}
+                                    style={{ cursor: "pointer" }}
+                                    className="rounded-lg border border-blue-600 bg-white px-4 py-2 text-sm font-medium text-blue-700 hover:bg-blue-50 transition"
+                                  >
+                                    Work through this
+                                  </button>
+                                </div>
+                              )}
+                            </div>
+                          );
+                        })}
+                      </div>
+
+                      {/* Done for now — separate visual area */}
+                      {doneForNowIds.length > 0 && (
+                        <div className="pt-3 border-t border-gray-200">
+                          <h3 className="mb-2 text-[11px] font-medium tracking-widest uppercase text-gray-300">
+                            Done for now
+                          </h3>
+                          <div className="space-y-1">
+                            {graph.nodes.filter(
+                              (n) => doneForNowIds.includes(n.id)
+                            ).map((node) => (
+                              <div key={node.id} className="rounded-lg border border-gray-200/60 bg-gray-50/40 px-4 py-3">
+                                <p className="text-sm text-gray-500 leading-snug">{node.label}</p>
+                                <button
+                                  onClick={() => setDoneForNowIds(doneForNowIds.filter(id => id !== node.id))}
+                                  style={{ cursor: "pointer" }}
+                                  className="mt-2 rounded border border-gray-300 px-3 py-1 text-xs font-medium text-gray-500 hover:bg-white transition"
+                                >
+                                  Reopen
+                                </button>
+                              </div>
+                            ))}
+                          </div>
+                        </div>
+                      )}
                     </div>
-                    <div className="flex items-center justify-between">
-                      <p className="text-xs text-gray-400">
-                        One update turn only in this prototype.
-                      </p>
+                  );
+                })()}
+
+                {/* ── Focused question workspace ── */}
+                {focusedPresentationItemId !== null && (() => {
+                  const focusedNode = graph?.nodes.find(
+                    (n) => n.id === focusedPresentationItemId,
+                  );
+                  const hasReasoningSupport = result?.selectedQuestion?.nodeId === focusedPresentationItemId;
+
+                  return (
+                    <div className="space-y-5">
                       <button
-                        type="submit"
-                        disabled={!answer.trim()}
-                        className="rounded-lg bg-blue-700 px-5 py-2.5 text-sm font-medium text-white transition hover:bg-blue-600 disabled:cursor-not-allowed disabled:opacity-40"
+                        onClick={() => setFocusedPresentationItemId(null)}
+                        style={{ cursor: "pointer" }}
+                        className="text-sm text-gray-400 underline hover:text-gray-600 transition"
                       >
-                        Update
+                        Back to open questions
+                      </button>
+
+                      {hasReasoningSupport && (
+                        <div className="space-y-3">
+                          <div className="text-xs text-gray-400">
+                            Chosen investigation: {" "}
+                            {focusedNode?.label}
+                          </div>
+                          <CurrentInvestigationCard selectedQuestion={selectedQ} graph={graph} />
+                        </div>
+                      )}
+
+                      {!hasReasoningSupport && (
+                        <div className="rounded-lg border border-gray-200/60 bg-gray-100/50 px-8 py-6 text-center">
+                          <p className="text-sm leading-relaxed text-gray-500">
+                            We have not explored this yet.
+                          </p>
+                        </div>
+                      )}
+
+                      {updateStatus === "success" && !isUpdating && (
+                        <UpdateAcknowledgement updateResult={result} />
+                      )}
+
+                      {/* Answer form — only when focused item matches Engine question */}
+                      {!isUpdating && hasReasoningSupport && canAnswer && (
+                        <form onSubmit={handleUpdateCaptureAndSubmit} className="space-y-4 rounded-lg border border-gray-200 bg-white p-5">
+                          <div>
+                            <label htmlFor="rw-answer" className="mb-2 block text-sm font-medium text-gray-700">
+                              Response
+                            </label>
+                            <textarea
+                              id="rw-answer"
+                              value={answer}
+                              onChange={(e) => setAnswer(e.target.value)}
+                              rows={4}
+                              disabled={updateStatus === "loading"}
+                              data-testid="response-textarea"
+                              className="w-full rounded-lg border border-gray-300 px-4 py-3 text-sm focus:border-gray-500 focus:outline-none focus:ring-2 focus:ring-gray-400 disabled:cursor-not-allowed disabled:opacity-60"
+                              placeholder="What do you know about this?"
+                            />
+                          </div>
+                          <div className="flex items-center justify-between">
+                            <p className="text-xs text-gray-400">
+                              One update turn only in this prototype.
+                            </p>
+                            <button
+                              type="submit"
+                              disabled={!answer.trim()}
+                              className="rounded-lg bg-blue-700 px-5 py-2.5 text-sm font-medium text-white transition hover:bg-blue-600 disabled:cursor-not-allowed disabled:opacity-40"
+                            >
+                              Update
+                            </button>
+                          </div>
+                        </form>
+                      )}
+
+                      <button
+                        onClick={() => {
+                          setFocusedPresentationItemId(null);
+                          setDoneForNowIds((prev) => [...prev, focusedPresentationItemId]);
+                        }}
+                        style={{ cursor: "pointer" }}
+                        className="rounded-lg border border-gray-300 bg-white px-4 py-2 text-sm font-medium text-gray-600 hover:bg-gray-50 transition"
+                      >
+                        Done for now
                       </button>
                     </div>
-                  </form>
-                )}
+                  );
+                })()}
 
                 {/* Terminal state */}
                 {status === "success" && !hasSelectedQuestion && (