From ff84d85eb3ea8e8b1fe17d86614958b0091592da Mon Sep 17 00:00:00 2001
From: Julian Appel <kontakt@julianappel.de>
Date: Thu, 23 Jul 2026 17:49:50 +0200
Subject: [PATCH] Show placeholders in empty circuit lists

---
 src/frontend/utils/circuit-grid-projection.ts |  2 +-
 tests/circuit-grid-projection.test.ts         | 35 +++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/frontend/utils/circuit-grid-projection.ts b/src/frontend/utils/circuit-grid-projection.ts
index a5bda32..b3e2dfc 100644
--- a/src/frontend/utils/circuit-grid-projection.ts
+++ b/src/frontend/utils/circuit-grid-projection.ts
@@ -113,7 +113,7 @@ export function filterAndSortCircuitSections(
 
       return { ...section, circuits };
     })
-    .filter((section) => section.circuits.length > 0);
+    .filter((section) => activeFilters.length === 0 || section.circuits.length > 0);
 }
 
 function makeVisibleGridRow(
diff --git a/tests/circuit-grid-projection.test.ts b/tests/circuit-grid-projection.test.ts
index e5f1f9a..dde8b5d 100644
--- a/tests/circuit-grid-projection.test.ts
+++ b/tests/circuit-grid-projection.test.ts
@@ -78,6 +78,41 @@ const sections: CircuitTreeSectionDto[] = [
 ];
 
 describe("circuit grid projection", () => {
+  it("keeps empty sections and their free placeholders when no filter is active", () => {
+    const emptySections: CircuitTreeSectionDto[] = [
+      {
+        id: "empty-lighting",
+        key: "lighting",
+        displayName: "Lighting",
+        prefix: "-1F",
+        sortOrder: 10,
+        circuits: [],
+      },
+      {
+        id: "empty-single-phase",
+        key: "single_phase",
+        displayName: "Single-phase circuits",
+        prefix: "-2F",
+        sortOrder: 20,
+        circuits: [],
+      },
+    ];
+
+    const projectedSections = filterAndSortCircuitSections(emptySections, {}, null);
+    const rows = buildVisibleGridRows(projectedSections);
+
+    assert.equal(projectedSections.length, 2);
+    assert.deepEqual(
+      rows.map((row) => row.rowKey),
+      [
+        "section:empty-lighting",
+        "placeholder:empty-lighting",
+        "section:empty-single-phase",
+        "placeholder:empty-single-phase",
+      ]
+    );
+  });
+
   it("keeps every device row in a circuit block when one device matches a filter", () => {
     const result = filterAndSortCircuitSections(sections, { roomNumberSnapshot: ["1.01"] }, null);