diff --git a/client_v2/src/lib/components/ExtraFieldsSection.svelte b/client_v2/src/lib/components/ExtraFieldsSection.svelte
index 2a4b9c11..e5c1c848 100644
--- a/client_v2/src/lib/components/ExtraFieldsSection.svelte
+++ b/client_v2/src/lib/components/ExtraFieldsSection.svelte
@@ -22,8 +22,16 @@
 		 * another entity, where an empty section is just noise.
 		 */
 		manage?: boolean;
+		/**
+		 * Emit only the field rows — no section header, no grid of its own — so the
+		 * caller can drop them straight into its own <FieldGrid>. Used by the
+		 * read-only mirrors of another entity, where a second "Extra fields" heading
+		 * in the same panel reads as a peer section rather than as more of the
+		 * entity above it (#992).
+		 */
+		headless?: boolean;
 	}
-	let { entity, extra, onchange, readonly = false, manage = false }: Props = $props();
+	let { entity, extra, onchange, readonly = false, manage = false, headless = false }: Props = $props();
 
 	$effect(() => {
 		fields.ensure(entity);
@@ -43,20 +51,21 @@
 	>
 {/snippet}
 
-{#if show}
+{#snippet rows()}
+	{#each defs as f (f.key)}
+		<Field label={f.name}>
+			<ExtraFieldInput field={f} value={extra[f.key]} onchange={(json) => onchange(f.key, json)} {readonly} />
+		</Field>
+	{/each}
+{/snippet}
+
+{#if headless}
+	{@render rows()}
+{:else if show}
 	<SectionLabel right={manage ? manageLink : undefined}>{m['settings.extraFields.tab']()}</SectionLabel>
 	{#if defs.length}
 		<FieldGrid>
-			{#each defs as f (f.key)}
-				<Field label={f.name}>
-					<ExtraFieldInput
-						field={f}
-						value={extra[f.key]}
-						onchange={(json) => onchange(f.key, json)}
-						{readonly}
-					/>
-				</Field>
-			{/each}
+			{@render rows()}
 		</FieldGrid>
 	{:else}
 		<div class="none">{m['inspector.noExtraFields']()}</div>
diff --git a/client_v2/src/lib/components/library/SpoolInspector.svelte b/client_v2/src/lib/components/library/SpoolInspector.svelte
index 9ed430e1..c066fcab 100644
--- a/client_v2/src/lib/components/library/SpoolInspector.svelte
+++ b/client_v2/src/lib/components/library/SpoolInspector.svelte
@@ -376,10 +376,12 @@
 				{/if}
 				<Field label={m['filament.fields.registered']()}>{filament.registeredLabel}</Field>
 				<Field label={m['filament.fields.comment']()}><LinkedText text={filament.comment} /></Field>
+				<!-- The filament's own custom fields, as further rows of this grid: a
+				     second "Extra fields" heading here would read as a peer of FILAMENT
+				     and MANUFACTURER rather than as more of the filament. -->
+				<ExtraFieldsSection entity="filament" extra={filament.extra} onchange={() => {}} readonly headless />
 			</FieldGrid>
 
-			<ExtraFieldsSection entity="filament" extra={filament.extra} onchange={() => {}} readonly />
-
 			<VendorSection
 				{vendor}
 				href={vendor ? params.selectHref(page.url.searchParams, 'vendor', vendor.id) : undefined}
diff --git a/client_v2/src/lib/components/library/VendorSection.svelte b/client_v2/src/lib/components/library/VendorSection.svelte
index 96e7fb6a..ca5666c8 100644
--- a/client_v2/src/lib/components/library/VendorSection.svelte
+++ b/client_v2/src/lib/components/library/VendorSection.svelte
@@ -47,9 +47,10 @@
 		{/if}
 		<Field label={m['vendor.fields.registered']()}>{vendor.registeredLabel}</Field>
 		<Field label={m['vendor.fields.comment']()}><LinkedText text={vendor.comment} /></Field>
+		<!-- Rows of this same grid rather than their own headed section — see the
+		     `headless` prop's note in ExtraFieldsSection. -->
+		<ExtraFieldsSection entity="vendor" extra={vendor.extra} onchange={() => {}} readonly headless />
 	</FieldGrid>
-
-	<ExtraFieldsSection entity="vendor" extra={vendor.extra} onchange={() => {}} readonly />
 {:else}
 	<div class="none">{m['add.noManufacturer']()}</div>
 {/if}