diff --git a/src/__tests__/renderer/utils/tabHelpers.test.ts b/src/__tests__/renderer/utils/tabHelpers.test.ts
index 4b13ff1b..deab62eb 100644
--- a/src/__tests__/renderer/utils/tabHelpers.test.ts
+++ b/src/__tests__/renderer/utils/tabHelpers.test.ts
@@ -72,6 +72,9 @@ function createMockSession(overrides: Partial<Session> = {}): Session {
 		aiTabs: [],
 		activeTabId: '',
 		closedTabHistory: [],
+		filePreviewTabs: [],
+		activeFileTabId: null,
+		unifiedTabOrder: [],
 		...overrides,
 	};
 }
@@ -578,6 +581,22 @@ describe('tabHelpers', () => {
 			expect(result!.session.activeTabId).toBe('tab-2');
 			expect(result!.tab).toBe(tab2);
 		});
+
+		it('clears activeFileTabId when selecting an AI tab', () => {
+			const tab = createMockTab({ id: 'tab-1' });
+			const session = createMockSession({
+				aiTabs: [tab],
+				activeTabId: 'tab-1',
+				activeFileTabId: 'file-tab-1', // A file tab was active
+			});
+
+			const result = setActiveTab(session, 'tab-1');
+
+			// Should return a new session with activeFileTabId cleared
+			expect(result!.session).not.toBe(session);
+			expect(result!.session.activeFileTabId).toBeNull();
+			expect(result!.session.activeTabId).toBe('tab-1');
+		});
 	});
 
 	describe('getWriteModeTab', () => {
diff --git a/src/renderer/utils/tabHelpers.ts b/src/renderer/utils/tabHelpers.ts
index 8ee55ba8..07dbbeed 100644
--- a/src/renderer/utils/tabHelpers.ts
+++ b/src/renderer/utils/tabHelpers.ts
@@ -440,19 +440,22 @@ export function setActiveTab(session: Session, tabId: string): SetActiveTabResul
 		return null;
 	}
 
-	// If already active, return current state (no mutation needed)
-	if (session.activeTabId === tabId) {
+	// If already active and no file tab is selected, return current state (no mutation needed)
+	if (session.activeTabId === tabId && session.activeFileTabId === null) {
 		return {
 			tab: targetTab,
 			session,
 		};
 	}
 
+	// When selecting an AI tab, deselect any active file preview tab
+	// This ensures only one tab type (AI or file) is active at a time
 	return {
 		tab: targetTab,
 		session: {
 			...session,
 			activeTabId: tabId,
+			activeFileTabId: null,
 		},
 	};
 }