diff --git a/app/frontend/components/Chat.tsx b/app/frontend/components/Chat.tsx
index 17a50eca..a2f2f6b5 100644
--- a/app/frontend/components/Chat.tsx
+++ b/app/frontend/components/Chat.tsx
@@ -376,7 +376,7 @@ function MessageViewWithCitations({
 						if (latestCitations.length > 0) {
 							result.push(
 								<CitationBlock
-									key={`citations-${i}`}
+									key={`citations-${msg.id}`}
 									citations={latestCitations}
 								/>,
 							);
diff --git a/app/frontend/components/CitationBlock.tsx b/app/frontend/components/CitationBlock.tsx
index b4c463bd..3221e0ec 100644
--- a/app/frontend/components/CitationBlock.tsx
+++ b/app/frontend/components/CitationBlock.tsx
@@ -1,6 +1,6 @@
 "use client";
 
-import { useCallback, useState } from "react";
+import { useCallback, useEffect, useRef, useState } from "react";
 import type { Citation } from "../lib/sessionStorage";
 
 interface CitationBlockProps {
@@ -73,8 +73,20 @@ export default function CitationBlock({ citations }: CitationBlockProps) {
 		loading: false,
 		error: null,
 	});
+	// AbortController for the in-flight visualize fetch so a rapid close/reopen
+	// doesn't let a stale response overwrite the new request's state.
+	const abortRef = useRef<AbortController | null>(null);
+
+	// Abort any in-flight request on unmount.
+	useEffect(() => {
+		return () => abortRef.current?.abort();
+	}, []);
 
 	const fetchVisualGrounding = useCallback(async (chunkId: string) => {
+		abortRef.current?.abort();
+		const controller = new AbortController();
+		abortRef.current = controller;
+
 		setVisualGrounding({
 			isOpen: true,
 			chunkId,
@@ -84,10 +96,12 @@ export default function CitationBlock({ citations }: CitationBlockProps) {
 		});
 
 		try {
-			const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || "";
-			const response = await fetch(`${backendUrl}/api/visualize/${chunkId}`);
+			const response = await fetch(`/api/visualize/${chunkId}`, {
+				signal: controller.signal,
+			});
 			const data = await response.json();
 
+			if (controller.signal.aborted) return;
 			if (!response.ok) {
 				throw new Error(data.error || "Failed to fetch visual grounding");
 			}
@@ -99,6 +113,7 @@ export default function CitationBlock({ citations }: CitationBlockProps) {
 				error: data.images?.length === 0 ? data.message : null,
 			}));
 		} catch (err) {
+			if (controller.signal.aborted) return;
 			setVisualGrounding((prev) => ({
 				...prev,
 				loading: false,
@@ -108,6 +123,8 @@ export default function CitationBlock({ citations }: CitationBlockProps) {
 	}, []);
 
 	const closeVisualGrounding = useCallback(() => {
+		abortRef.current?.abort();
+		abortRef.current = null;
 		setVisualGrounding({
 			isOpen: false,
 			chunkId: null,
diff --git a/app/frontend/components/DbInfo.tsx b/app/frontend/components/DbInfo.tsx
index 8f50ffa8..7d0869d3 100644
--- a/app/frontend/components/DbInfo.tsx
+++ b/app/frontend/components/DbInfo.tsx
@@ -25,8 +25,7 @@ export default function DbInfo() {
 	const [error, setError] = useState<string | null>(null);
 
 	useEffect(() => {
-		const backendUrl = process.env.NEXT_PUBLIC_BACKEND_URL || "";
-		fetch(`${backendUrl}/api/info`)
+		fetch("/api/info")
 			.then((res) => res.json())
 			.then(setInfo)
 			.catch((err) => setError(err.message));
diff --git a/app/frontend/components/DocumentFilter.tsx b/app/frontend/components/DocumentFilter.tsx
index d2296961..1fa56d46 100644
--- a/app/frontend/components/DocumentFilter.tsx
+++ b/app/frontend/components/DocumentFilter.tsx
@@ -16,6 +16,8 @@ interface DocumentFilterProps {
 	onApply: (selected: string[]) => void;
 }
 
+const getDisplayName = (doc: Document) => doc.title || doc.uri || doc.id;
+
 export default function DocumentFilter({
 	isOpen,
 	onClose,
@@ -26,33 +28,40 @@ export default function DocumentFilter({
 	const [documents, setDocuments] = useState<Document[]>([]);
 	const [loading, setLoading] = useState(true);
 	const [searchTerm, setSearchTerm] = useState("");
-	const [localSelected, setLocalSelected] = useState<Set<string>>(
-		new Set(selected),
-	);
+	// Track selection by document id — two docs can share a title, but ids
+	// are unique. Display names are only used for rendering and for the
+	// filter string returned to the parent.
+	const [localSelected, setLocalSelected] = useState<Set<string>>(new Set());
 
-	// Reset local state when modal opens
+	// Refetch on every open so newly-added or deleted documents show up.
 	useEffect(() => {
-		if (isOpen) {
-			setLocalSelected(new Set(selected));
-			setSearchTerm("");
-		}
-	}, [isOpen, selected]);
+		if (!isOpen) return;
+		setLoading(true);
+		fetch("/api/documents")
+			.then((res) => res.json())
+			.then((data) => {
+				setDocuments(data.documents || []);
+				setLoading(false);
+			})
+			.catch(() => {
+				setLoading(false);
+			});
+	}, [isOpen]);
 
-	// Fetch documents when modal opens
+	// Seed local selection from the parent's display-name list once documents
+	// are available. Any doc whose display name is in `selected` starts checked.
 	useEffect(() => {
-		if (isOpen && documents.length === 0) {
-			setLoading(true);
-			fetch("/api/documents")
-				.then((res) => res.json())
-				.then((data) => {
-					setDocuments(data.documents || []);
-					setLoading(false);
-				})
-				.catch(() => {
-					setLoading(false);
-				});
-		}
-	}, [isOpen, documents.length]);
+		if (!isOpen) return;
+		const selectedNames = new Set(selected);
+		setLocalSelected(
+			new Set(
+				documents
+					.filter((d) => selectedNames.has(getDisplayName(d)))
+					.map((d) => d.id),
+			),
+		);
+		setSearchTerm("");
+	}, [isOpen, selected, documents]);
 
 	const handleKeyDown = useCallback(
 		(e: React.KeyboardEvent) => {
@@ -63,20 +72,24 @@ export default function DocumentFilter({
 		[onClose],
 	);
 
-	const toggleDocument = (displayName: string) => {
+	const toggleDocument = (docId: string) => {
 		setLocalSelected((prev) => {
 			const next = new Set(prev);
-			if (next.has(displayName)) {
-				next.delete(displayName);
+			if (next.has(docId)) {
+				next.delete(docId);
 			} else {
-				next.add(displayName);
+				next.add(docId);
 			}
 			return next;
 		});
 	};
 
 	const handleApply = () => {
-		onApply(Array.from(localSelected));
+		const names = documents
+			.filter((d) => localSelected.has(d.id))
+			.map(getDisplayName);
+		// Dedupe: two selected docs sharing a title collapse to one filter term.
+		onApply(Array.from(new Set(names)));
 		onClose();
 	};
 
@@ -84,8 +97,6 @@ export default function DocumentFilter({
 		setLocalSelected(new Set());
 	};
 
-	const getDisplayName = (doc: Document) => doc.title || doc.uri || doc.id;
-
 	const filteredDocuments = documents.filter((doc) => {
 		if (!searchTerm) return true;
 		const displayName = getDisplayName(doc).toLowerCase();
@@ -144,8 +155,8 @@ export default function DocumentFilter({
 								<label key={doc.id} className="filter-item">
 									<input
 										type="checkbox"
-										checked={localSelected.has(displayName)}
-										onChange={() => toggleDocument(displayName)}
+										checked={localSelected.has(doc.id)}
+										onChange={() => toggleDocument(doc.id)}
 									/>
 									<span className="filter-item-label">{displayName}</span>
 								</label>