diff --git a/src/panel/panel.ts b/src/panel/panel.ts
index b69eddf..f285968 100644
--- a/src/panel/panel.ts
+++ b/src/panel/panel.ts
@@ -11,8 +11,9 @@ export interface StatusPanelInput {
    *  Omit to hide the version line. */
   version?: string;
   /** Host session accounting — the SAME number the host footer displays.
-   *  It is the append-only session tree including compressed originals; it
-   *  never shrinks when compression prunes the per-request view. */
+   *  It includes compressed originals (summaries stay in the window), so it
+   *  shrinks slower than the sent view when compression prunes the
+   *  per-request projection. */
   tokenCount: number;
   /** Measured token count of the host system prompt (host-specific to
    *  obtain; the kernel breakdown does not see it). */
@@ -49,9 +50,10 @@ function bar(value: number, total: number, width: number = 20): string {
 
 /** Render the /acp status panel. Three token numbers, each labeled with
  *  its own scale, never mixed in arithmetic:
- *  - Session accounting (host footer scale): the append-only session tree
- *    INCLUDING compressed originals. It never shrinks — adapter pruning is
- *    a per-request transform view the host cannot see.
+ *  - Session accounting (host footer scale): the host's reported context
+ *    size INCLUDING compressed originals (summaries stay in the window), so
+ *    it shrinks slower than the sent view when compression prunes the
+ *    per-request projection.
  *  - Sent view (estimated, kernel countTokens scale): what actually
  *    reaches the LLM after compression (kernel's classification over the
  *    pruned projection + measured system prompt). This is the number
@@ -88,7 +90,7 @@ export function buildStatusPanel(input: StatusPanelInput): string {
   lines.push("╰─────────────────────────────────────────────╯");
   if (input.version) lines.push(input.version);
   lines.push("");
-  lines.push(`Context (session accounting, host footer scale): ${displayPct}% (${fmt(displayTotal)} / ${fmt(limit)}) — never shrinks; includes compressed originals`);
+  lines.push(`Context (session accounting, host footer scale): ${displayPct}% (${fmt(displayTotal)} / ${fmt(limit)}) — includes compressed originals; shrinks slower than the sent view`);
 
   if (nudge && bd) {
     const growth = bd.growth;
@@ -149,7 +151,7 @@ export function buildStatusPanel(input: StatusPanelInput): string {
 
   if (activeBlocksList.length > 0) {
     lines.push("");
-    lines.push(`Blocks: ${activeBlocksList.length} active / ${totalBlocksList.length} total (${fmt(state.stats.tokensCompressed)} tokens compressed)`);
+    lines.push(`Blocks: ${activeBlocksList.length} active / ${totalBlocksList.length} total (${fmt(state.stats.tokensCompressed)} tokens compressed, cumulative)`);
     for (const b of activeBlocksList) {
       const topic = b.topic ? `: ${b.topic}` : `: ${topicFallback(b.summary || "")}`;
       const summaryTok = defaultCountTokens(b.summary || "");
@@ -158,7 +160,7 @@ export function buildStatusPanel(input: StatusPanelInput): string {
     }
   } else if (totalBlocksList.length > 0) {
     lines.push("");
-    lines.push(`Blocks: 0 active / ${totalBlocksList.length} total (${fmt(state.stats.tokensCompressed)} tokens compressed)`);
+    lines.push(`Blocks: 0 active / ${totalBlocksList.length} total (${fmt(state.stats.tokensCompressed)} tokens compressed, cumulative)`);
   } else {
     lines.push("");
     lines.push("Blocks: none (nothing compressed yet)");
diff --git a/src/sync.ts b/src/sync.ts
index ab14deb..08a62bc 100644
--- a/src/sync.ts
+++ b/src/sync.ts
@@ -64,6 +64,14 @@ export function syncBlocks(
       block.active = false;
       continue;
     }
+    // Host-set `expanded` = the user explicitly decompressed this block, so its
+    // deactivated state is intentional. Re-activating it here would re-fold the
+    // already-restored messages next turn (double cost + lost originals). Keep
+    // it inactive; a fresh compress of the same range creates a NEW block.
+    if (block.expanded) {
+      block.active = false;
+      continue;
+    }
     block.active = true;
     // A block whose raw messages were replaced by its rendered summary
     // (pruned view) is still present — the summary IS the block's visible
diff --git a/src/types.ts b/src/types.ts
index 9bc8377..f7a4ea5 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -31,6 +31,12 @@ export interface CompressionBlock {
   survivedCount: number;
   generation: BlockGeneration;
   active: boolean;
+  /** Host-set: the user explicitly decompressed (expanded) this block, so its
+   *  deactivated state is intentional and must survive syncBlocks re-activation.
+   *  Absent/false for blocks deactivated by other means (orphan GC, tier
+   *  distillation, consumed-by-parent) — those keep the legacy resurrection
+   *  behavior. */
+  expanded?: boolean;
   durationMs?: number;
   compressCallId?: string;
   startRef?: string;
diff --git a/tests/panel.test.ts b/tests/panel.test.ts
index 063c41a..1fcf962 100644
--- a/tests/panel.test.ts
+++ b/tests/panel.test.ts
@@ -33,7 +33,7 @@ test("panel separates session accounting from sent view", () => {
     modelContextLimit: 1_000_000,
   });
 
-  assert.match(text, /Context \(session accounting, host footer scale\): 43% \(430k \/ 1\.0M\) — never shrinks/);
+  assert.match(text, /Context \(session accounting, host footer scale\): 43% \(430k \/ 1\.0M\) — includes compressed originals; shrinks slower than the sent view/);
   assert.match(text, /Sent to LLM \(after compression, est\.\): 24k \(2% of limit\)/);
   assert.doesNotMatch(text, /Session-only/, "omitted without unprunedTokens — no cross-scale subtraction");
   assert.match(text, /Token Breakdown \(sent view\):/);
@@ -55,7 +55,7 @@ test("panel renders blocks with topic fallback and version line", () => {
     nextRunId: 1,
   };
   const text = buildStatusPanel({ tokenCount: 1_000, systemPromptTokens: 0, state: state as never, nudge: undefined, modelContextLimit: 200_000 });
-  assert.match(text, /Blocks: 1 active \/ 1 total \(25k tokens compressed\)/);
+  assert.match(text, /Blocks: 1 active \/ 1 total \(25k tokens compressed, cumulative\)/);
   assert.match(text, /\[b1\] T1 25k→\d+.*Plugin discovery and registrat…/);
   assert.doesNotMatch(text, /acp-kernel@/, "no version line when omitted");
 });
diff --git a/tests/sync-config.test.ts b/tests/sync-config.test.ts
index 249b4ce..75e7bcc 100644
--- a/tests/sync-config.test.ts
+++ b/tests/sync-config.test.ts
@@ -50,6 +50,25 @@ test("syncBlocks leaves blocks intact when at least one message remains", () =>
   assert.equal(result.state.blocks[0]!.active, true);
 });
 
+test("syncBlocks keeps expanded (user-decompressed) blocks deactivated when present", () => {
+  const state = createInitialState();
+  state.blocks.push(
+    makeBlock({ blockId: "b1", effectiveMessageIds: ["a", "b"], active: false, expanded: true }),
+  );
+  const result = syncBlocks([msg("a"), msg("b")], state);
+  assert.equal(result.state.blocks[0]!.active, false, "expanded block must stay deactivated");
+  assert.deepEqual(result.deactivated, [], "expanded block is not reported as orphaned");
+});
+
+test("syncBlocks re-activates a deactivated (non-expanded) block when its messages return", () => {
+  const state = createInitialState();
+  state.blocks.push(
+    makeBlock({ blockId: "b1", effectiveMessageIds: ["a", "b"], active: false }),
+  );
+  const result = syncBlocks([msg("a"), msg("b")], state);
+  assert.equal(result.state.blocks[0]!.active, true, "legacy resurrection preserved for non-expanded blocks");
+});
+
 test("syncBlocks does not mutate input state", () => {
   const state = createInitialState();
   state.blocks.push(makeBlock({ blockId: "b1", effectiveMessageIds: ["x"] }));