diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6e6a0a343..dc4830825 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Health monitor now detects stuck queries beyond the configured timeout
 - SSH tunnel closure errors now logged instead of silently discarded
 - Schema/database restore errors during reconnect now logged
+- Memory not released after closing tabs
+- New tabs opening as separate windows instead of joining the connection tab group
+- Clicking tables in sidebar not opening table tabs
 
 ## [0.23.1] - 2026-03-24
 
diff --git a/LocalPackages/CodeEditSourceEditor/Sources/CodeEditSourceEditor/Controller/TextViewController.swift b/LocalPackages/CodeEditSourceEditor/Sources/CodeEditSourceEditor/Controller/TextViewController.swift
index fb95c81c1..22fbdc795 100644
--- a/LocalPackages/CodeEditSourceEditor/Sources/CodeEditSourceEditor/Controller/TextViewController.swift
+++ b/LocalPackages/CodeEditSourceEditor/Sources/CodeEditSourceEditor/Controller/TextViewController.swift
@@ -290,9 +290,31 @@ public class TextViewController: NSViewController {
         self.gutterView.setNeedsDisplay(self.gutterView.frame)
     }
 
+    /// Release heavy resources (tree-sitter, highlighter, text storage) early,
+    /// without waiting for deinit. Call when the editor is no longer visible but
+    /// SwiftUI may keep the controller alive in @State.
+    public func releaseHeavyState() {
+        if let highlighter {
+            textView?.removeStorageDelegate(highlighter)
+        }
+        highlighter = nil
+        treeSitterClient = nil
+        highlightProviders.removeAll()
+        // Don't call textCoordinators.destroy() here — the caller (coordinator.destroy())
+        // is already a coordinator, so calling back into destroy() causes infinite recursion.
+        textCoordinators.removeAll()
+        cancellables.forEach { $0.cancel() }
+        cancellables.removeAll()
+        if let localEventMonitor {
+            NSEvent.removeMonitor(localEventMonitor)
+        }
+        localEventMonitor = nil
+        textView?.setText("")
+    }
+
     deinit {
         if let highlighter {
-            textView.removeStorageDelegate(highlighter)
+            textView?.removeStorageDelegate(highlighter)
         }
         highlighter = nil
         highlightProviders.removeAll()
diff --git a/TablePro/AppDelegate+WindowConfig.swift b/TablePro/AppDelegate+WindowConfig.swift
index e575a6b99..f443d2bfd 100644
--- a/TablePro/AppDelegate+WindowConfig.swift
+++ b/TablePro/AppDelegate+WindowConfig.swift
@@ -107,15 +107,18 @@ extension AppDelegate {
     }
 
     func isMainWindow(_ window: NSWindow) -> Bool {
-        window.identifier?.rawValue == WindowId.main
+        guard let rawValue = window.identifier?.rawValue else { return false }
+        return rawValue == WindowId.main || rawValue.hasPrefix("\(WindowId.main)-")
     }
 
     func isWelcomeWindow(_ window: NSWindow) -> Bool {
-        window.identifier?.rawValue == WindowId.welcome
+        guard let rawValue = window.identifier?.rawValue else { return false }
+        return rawValue == WindowId.welcome || rawValue.hasPrefix("\(WindowId.welcome)-")
     }
 
     private func isConnectionFormWindow(_ window: NSWindow) -> Bool {
-        window.identifier?.rawValue == WindowId.connectionForm
+        guard let rawValue = window.identifier?.rawValue else { return false }
+        return rawValue == WindowId.connectionForm || rawValue.hasPrefix("\(WindowId.connectionForm)-")
     }
 
     // MARK: - Welcome Window
@@ -239,15 +242,26 @@ extension AppDelegate {
             let existingIdentifier = NSApp.windows
                 .first { $0 !== window && isMainWindow($0) && $0.isVisible }?
                 .tabbingIdentifier
-            window.tabbingIdentifier = TabbingIdentifierResolver.resolve(
+            let resolvedIdentifier = TabbingIdentifierResolver.resolve(
                 pendingConnectionId: pendingId,
                 existingIdentifier: existingIdentifier
             )
+            window.tabbingIdentifier = resolvedIdentifier
             configuredWindows.insert(windowId)
 
             if !NSWindow.allowsAutomaticWindowTabbing {
                 NSWindow.allowsAutomaticWindowTabbing = true
             }
+
+            // Explicitly attach to existing tab group — automatic tabbing
+            // doesn't work when tabbingIdentifier is set after window creation.
+            if let existingWindow = NSApp.windows.first(where: {
+                $0 !== window && isMainWindow($0) && $0.isVisible
+                    && $0.tabbingIdentifier == resolvedIdentifier
+            }) {
+                existingWindow.addTabbedWindow(window, ordered: .above)
+                window.makeKeyAndOrderFront(nil)
+            }
         }
     }
 
@@ -317,8 +331,8 @@ extension AppDelegate {
     }
 
     func closeRestoredMainWindows() {
-        DispatchQueue.main.async {
-            for window in NSApp.windows where window.identifier?.rawValue.contains("main") == true {
+        DispatchQueue.main.async { [weak self] in
+            for window in NSApp.windows where self?.isMainWindow(window) == true {
                 window.close()
             }
         }
diff --git a/TablePro/ContentView.swift b/TablePro/ContentView.swift
index 9ee562e62..1bbf967f6 100644
--- a/TablePro/ContentView.swift
+++ b/TablePro/ContentView.swift
@@ -114,7 +114,8 @@ struct ContentView: View {
                 // Match by checking if the window is registered for our connectionId
                 // in WindowLifecycleMonitor (subtitle may not be set yet on first appear).
                 guard let notificationWindow = notification.object as? NSWindow,
-                      notificationWindow.identifier?.rawValue.contains("main") == true,
+                      let windowId = notificationWindow.identifier?.rawValue,
+                      windowId == "main" || windowId.hasPrefix("main-"),
                       let connectionId = payload?.connectionId
                 else { return }
 
diff --git a/TablePro/Extensions/NSApplication+WindowManagement.swift b/TablePro/Extensions/NSApplication+WindowManagement.swift
index 96c16f0ba..fd201eb4d 100644
--- a/TablePro/Extensions/NSApplication+WindowManagement.swift
+++ b/TablePro/Extensions/NSApplication+WindowManagement.swift
@@ -10,12 +10,14 @@
 import AppKit
 
 extension NSApplication {
-    /// Close all windows whose identifier contains the given ID.
-    /// Legacy workaround from when the minimum was macOS 13. Now that macOS 14+ is the minimum,
-    /// callers could use SwiftUI's `dismissWindow(id:)` instead.
+    /// Close all windows whose identifier matches the given ID (exact or SwiftUI-suffixed).
+    /// SwiftUI appends "-AppWindow-N" to WindowGroup IDs, so we match by prefix.
     func closeWindows(withId id: String) {
-        for window in windows where window.identifier?.rawValue.contains(id) == true {
-            window.close()
+        for window in windows {
+            guard let rawValue = window.identifier?.rawValue else { continue }
+            if rawValue == id || rawValue.hasPrefix("\(id)-") {
+                window.close()
+            }
         }
     }
 }
diff --git a/TablePro/Models/Query/QueryTab.swift b/TablePro/Models/Query/QueryTab.swift
index 5963cac2a..a58b187b4 100644
--- a/TablePro/Models/Query/QueryTab.swift
+++ b/TablePro/Models/Query/QueryTab.swift
@@ -7,6 +7,7 @@
 
 import Foundation
 import Observation
+import os
 import TableProPluginKit
 
 /// Type of tab
@@ -269,6 +270,13 @@ final class RowBuffer {
         self.rows = newRows
         isEvicted = false
     }
+
+    deinit {
+        #if DEBUG
+        Logger(subsystem: "com.TablePro", category: "RowBuffer")
+            .debug("RowBuffer deallocated — columns: \(self.columns.count), evicted: \(self.isEvicted)")
+        #endif
+    }
 }
 
 /// Represents a single tab (query or table)
@@ -676,4 +684,11 @@ final class QueryTabManager {
             tabs[index] = tab
         }
     }
+
+    deinit {
+        #if DEBUG
+        Logger(subsystem: "com.TablePro", category: "QueryTabManager")
+            .debug("QueryTabManager deallocated")
+        #endif
+    }
 }
diff --git a/TablePro/Models/Query/RowProvider.swift b/TablePro/Models/Query/RowProvider.swift
index ed91e419c..2a81e1a1d 100644
--- a/TablePro/Models/Query/RowProvider.swift
+++ b/TablePro/Models/Query/RowProvider.swift
@@ -66,7 +66,12 @@ final class TableRowData {
 /// Direct-access methods `value(atRow:column:)` and `rowValues(at:)` avoid
 /// heap allocations by reading straight from the source `[String?]` array.
 final class InMemoryRowProvider: RowProvider {
-    private let rowBuffer: RowBuffer
+    private weak var rowBuffer: RowBuffer?
+    /// Strong reference only when the provider created its own buffer (convenience init).
+    /// External buffers are owned by QueryTab, so we hold them weakly.
+    private var ownedBuffer: RowBuffer?
+    private static let emptyBuffer = RowBuffer()
+    private var safeBuffer: RowBuffer { rowBuffer ?? Self.emptyBuffer }
     private var sortIndices: [Int]?
     private var appendedRows: [[String?]] = []
     private(set) var columns: [String]
@@ -86,7 +91,7 @@ final class InMemoryRowProvider: RowProvider {
 
     /// Number of rows coming from the buffer (respecting sort indices count when present)
     private var bufferRowCount: Int {
-        sortIndices?.count ?? rowBuffer.rows.count
+        sortIndices?.count ?? safeBuffer.rows.count
     }
 
     init(
@@ -130,6 +135,7 @@ final class InMemoryRowProvider: RowProvider {
             columnEnumValues: columnEnumValues,
             columnNullable: columnNullable
         )
+        ownedBuffer = buffer
     }
 
     func fetchRows(offset: Int, limit: Int) -> [TableRowData] {
@@ -157,7 +163,8 @@ final class InMemoryRowProvider: RowProvider {
         guard rowIndex < totalRowCount else { return }
         let sourceIndex = resolveSourceIndex(rowIndex)
         if let bufferIdx = sourceIndex.bufferIndex {
-            rowBuffer.rows[bufferIdx][columnIndex] = value
+            guard let buffer = rowBuffer else { return }
+            buffer.rows[bufferIdx][columnIndex] = value
             displayCache.removeValue(forKey: bufferIdx)
         } else if let appendedIdx = sourceIndex.appendedIndex {
             appendedRows[appendedIdx][columnIndex] = value
@@ -215,9 +222,18 @@ final class InMemoryRowProvider: RowProvider {
         displayCache.removeAll()
     }
 
+    /// Release cached data to free memory when this provider is no longer active.
+    func releaseData() {
+        displayCache.removeAll()
+        appendedRows.removeAll()
+        sortIndices = nil
+        ownedBuffer = nil
+    }
+
     /// Update rows by replacing the buffer contents and clearing appended rows
     func updateRows(_ newRows: [[String?]]) {
-        rowBuffer.rows = newRows
+        guard let buffer = rowBuffer else { return }
+        buffer.rows = newRows
         appendedRows.removeAll()
         sortIndices = nil
         displayCache.removeAll()
@@ -240,9 +256,10 @@ final class InMemoryRowProvider: RowProvider {
             guard appendedIdx < appendedRows.count else { return }
             appendedRows.remove(at: appendedIdx)
         } else {
+            guard let buffer = rowBuffer else { return }
             if let sorted = sortIndices {
                 let bufferIdx = sorted[index]
-                rowBuffer.rows.remove(at: bufferIdx)
+                buffer.rows.remove(at: bufferIdx)
                 var newIndices = sorted
                 newIndices.remove(at: index)
                 for i in newIndices.indices where newIndices[i] > bufferIdx {
@@ -250,7 +267,7 @@ final class InMemoryRowProvider: RowProvider {
                 }
                 sortIndices = newIndices
             } else {
-                rowBuffer.rows.remove(at: index)
+                buffer.rows.remove(at: index)
             }
         }
         displayCache.removeAll()
@@ -297,9 +314,9 @@ final class InMemoryRowProvider: RowProvider {
             return appendedRows[displayIndex - bCount]
         }
         if let sorted = sortIndices {
-            return rowBuffer.rows[sorted[displayIndex]]
+            return safeBuffer.rows[sorted[displayIndex]]
         }
-        return rowBuffer.rows[displayIndex]
+        return safeBuffer.rows[displayIndex]
     }
 }
 
diff --git a/TablePro/Resources/Localizable.xcstrings b/TablePro/Resources/Localizable.xcstrings
index 569d2ca3c..43d9993db 100644
--- a/TablePro/Resources/Localizable.xcstrings
+++ b/TablePro/Resources/Localizable.xcstrings
@@ -27181,6 +27181,9 @@
           }
         }
       }
+    },
+    "SSH Connection Test Failed" : {
+
     },
     "SSH connection timed out" : {
       "localizations" : {
diff --git a/TablePro/Views/Editor/SQLEditorCoordinator.swift b/TablePro/Views/Editor/SQLEditorCoordinator.swift
index 53cb569d1..e19cfdb64 100644
--- a/TablePro/Views/Editor/SQLEditorCoordinator.swift
+++ b/TablePro/Views/Editor/SQLEditorCoordinator.swift
@@ -146,7 +146,22 @@ final class SQLEditorCoordinator: TextViewCoordinator {
         inlineSuggestionManager?.uninstall()
         inlineSuggestionManager = nil
 
+        // Release closure captures to break potential retain cycles
+        onCloseTab = nil
+        onExecuteQuery = nil
+        onAIExplain = nil
+        onAIOptimize = nil
+        onSaveAsFavorite = nil
+        schemaProvider = nil
+        contextMenu = nil
+        vimEngine = nil
+        vimCursorManager = nil
+
+        // Release editor controller heavy state
+        controller?.releaseHeavyState()
+
         EditorEventRouter.shared.unregister(self)
+        Self.logger.debug("SQLEditorCoordinator destroyed")
         cleanupMonitors()
     }
 
diff --git a/TablePro/Views/Editor/SQLEditorView.swift b/TablePro/Views/Editor/SQLEditorView.swift
index 07bdd4acc..c1e727931 100644
--- a/TablePro/Views/Editor/SQLEditorView.swift
+++ b/TablePro/Views/Editor/SQLEditorView.swift
@@ -126,6 +126,7 @@ struct SQLEditorView: View {
         .onDisappear {
             teardownFavoritesObserver()
             coordinator.destroy()
+            completionAdapter = nil
         }
         .onChange(of: coordinator.vimMode) { _, newMode in
             vimMode = newMode
diff --git a/TablePro/Views/Main/Child/MainEditorContentView.swift b/TablePro/Views/Main/Child/MainEditorContentView.swift
index 32a4910ed..a6aa331ef 100644
--- a/TablePro/Views/Main/Child/MainEditorContentView.swift
+++ b/TablePro/Views/Main/Child/MainEditorContentView.swift
@@ -147,6 +147,11 @@ struct MainEditorContentView: View {
             if let tab = tabManager.selectedTab {
                 cacheRowProvider(for: tab)
             }
+            coordinator.onTeardown = { [self] in
+                tabProviderCache.removeAll()
+                sortCache.removeAll()
+                cachedChangeManager = nil
+            }
         }
         .onChange(of: tabManager.selectedTab?.resultVersion) { _, newVersion in
             guard let tab = tabManager.selectedTab, newVersion != nil else { return }
diff --git a/TablePro/Views/Main/MainContentCoordinator.swift b/TablePro/Views/Main/MainContentCoordinator.swift
index 3698cd4dc..6ceb445e5 100644
--- a/TablePro/Views/Main/MainContentCoordinator.swift
+++ b/TablePro/Views/Main/MainContentCoordinator.swift
@@ -46,6 +46,10 @@ enum ActiveSheet: Identifiable {
 final class MainContentCoordinator {
     static let logger = Logger(subsystem: "com.TablePro", category: "MainContentCoordinator")
 
+    /// Posted during teardown so DataGridView coordinators can release cell views.
+    /// Object is the connection UUID.
+    static let teardownNotification = Notification.Name("MainContentCoordinator.teardown")
+
     // MARK: - Dependencies
 
     let connection: DatabaseConnection
@@ -125,6 +129,9 @@ final class MainContentCoordinator {
     /// (e.g. save-then-close). Set before calling `saveChanges`, resumed by `executeCommitStatements`.
     @ObservationIgnored internal var saveCompletionContinuation: CheckedContinuation<Bool, Never>?
 
+    /// Called during teardown to let the view layer release cached row providers and sort data.
+    @ObservationIgnored var onTeardown: (() -> Void)?
+
     /// True while a database switch is in progress. Guards against
     /// side-effect window creation during the switch cascade.
     var isSwitchingDatabase = false
@@ -338,6 +345,7 @@ final class MainContentCoordinator {
     /// synchronously on MainActor so we don't depend on deinit + Task scheduling.
     func teardown() {
         _didTeardown.withLock { $0 = true }
+
         unregisterFromPersistence()
         for observer in urlFilterObservers {
             NotificationCenter.default.removeObserver(observer)
@@ -360,15 +368,39 @@ final class MainContentCoordinator {
         for task in activeSortTasks.values { task.cancel() }
         activeSortTasks.removeAll()
 
+        // Let the view layer release cached row providers before we drop RowBuffers.
+        // Called synchronously here because SwiftUI onChange handlers don't fire
+        // reliably on disappearing views.
+        onTeardown?()
+        onTeardown = nil
+
+        // Notify DataGridView coordinators to release NSTableView cell views
+        NotificationCenter.default.post(
+            name: Self.teardownNotification,
+            object: connection.id
+        )
+
         // Release heavy data so memory drops even if SwiftUI delays deallocation
         for tab in tabManager.tabs {
             tab.rowBuffer.evict()
         }
         querySortCache.removeAll()
+        cachedTableColumnTypes.removeAll()
+        cachedTableColumnNames.removeAll()
 
         tabManager.tabs.removeAll()
         tabManager.selectedTabId = nil
 
+        // Release change manager state — pluginDriver holds a strong reference
+        // to the entire database driver which prevents deallocation
+        changeManager.clearChanges()
+        changeManager.pluginDriver = nil
+
+        // Release metadata and filter state
+        tableMetadata = nil
+        filterStateManager.filters.removeAll()
+        filterStateManager.appliedFilters.removeAll()
+
         SchemaProviderRegistry.shared.release(for: connection.id)
         SchemaProviderRegistry.shared.purgeUnused()
     }
diff --git a/TablePro/Views/Main/MainContentView.swift b/TablePro/Views/Main/MainContentView.swift
index b9742f119..90d66f6e6 100644
--- a/TablePro/Views/Main/MainContentView.swift
+++ b/TablePro/Views/Main/MainContentView.swift
@@ -253,6 +253,11 @@ struct MainContentView: View {
                     // Only handleTabsChange(count=0) clears state (user explicitly closed all tabs).
                     guard !WindowLifecycleMonitor.shared.hasWindows(for: connectionId) else { return }
                     await DatabaseManager.shared.disconnectSession(connectionId)
+
+                    // Give SwiftUI/AppKit time to deallocate view hierarchies,
+                    // then hint malloc to return freed pages to the OS
+                    try? await Task.sleep(for: .seconds(2))
+                    malloc_zone_pressure_relief(nil, 0)
                 }
             }
             .onChange(of: pendingChangeTrigger) {
@@ -595,6 +600,7 @@ struct MainContentView: View {
             isPreview: isPreview
         )
         viewWindow = window
+        isKeyWindow = window.isKeyWindow
 
         // Update command actions window reference now that it's available
         commandActions?.window = window
diff --git a/TablePro/Views/Results/DataGridView.swift b/TablePro/Views/Results/DataGridView.swift
index f63ff6aab..790ce3921 100644
--- a/TablePro/Views/Results/DataGridView.swift
+++ b/TablePro/Views/Results/DataGridView.swift
@@ -166,6 +166,9 @@ struct DataGridView: NSViewRepresentable {
 
         scrollView.documentView = tableView
         context.coordinator.tableView = tableView
+        if let connectionId {
+            context.coordinator.observeTeardown(connectionId: connectionId)
+        }
 
         return scrollView
     }
@@ -632,6 +635,7 @@ struct DataGridView: NSViewRepresentable {
             NotificationCenter.default.removeObserver(observer)
             coordinator.themeObserver = nil
         }
+        coordinator.rowProvider = InMemoryRowProvider(rows: [], columns: [])
     }
 
     func makeCoordinator() -> TableViewCoordinator {
@@ -839,6 +843,51 @@ final class TableViewCoordinator: NSObject, NSTableViewDelegate, NSTableViewData
         }
     }
 
+    /// Subscribe to coordinator teardown to release NSTableView cell views.
+    func observeTeardown(connectionId: UUID) {
+        teardownObserver = NotificationCenter.default.addObserver(
+            forName: MainContentCoordinator.teardownNotification,
+            object: connectionId,
+            queue: .main
+        ) { [weak self] _ in
+            self?.releaseData()
+        }
+    }
+
+    /// Release all data and cell views from the NSTableView.
+    /// Called during coordinator teardown to free memory while SwiftUI holds the view.
+    private func releaseData() {
+        overlayEditor?.dismiss(commit: false)
+        rowProvider = InMemoryRowProvider(rows: [], columns: [])
+        rowVisualStateCache.removeAll()
+        cachedRowCount = 0
+        cachedColumnCount = 0
+        // Remove columns and reload to release cell views
+        if let tableView {
+            while let col = tableView.tableColumns.last {
+                tableView.removeTableColumn(col)
+            }
+            tableView.reloadData()
+        }
+        // Release closures
+        onRefresh = nil
+        onCellEdit = nil
+        onDeleteRows = nil
+        onCopyRows = nil
+        onPasteRows = nil
+        onUndo = nil
+        onRedo = nil
+        onSort = nil
+        onAddRow = nil
+        onUndoInsert = nil
+        onFilterColumn = nil
+        onHideColumn = nil
+        onNavigateFK = nil
+        getVisualState = nil
+    }
+
+    private var teardownObserver: NSObjectProtocol?
+
     deinit {
         if let observer = settingsObserver {
             NotificationCenter.default.removeObserver(observer)
@@ -846,6 +895,9 @@ final class TableViewCoordinator: NSObject, NSTableViewDelegate, NSTableViewData
         if let observer = themeObserver {
             NotificationCenter.default.removeObserver(observer)
         }
+        if let observer = teardownObserver {
+            NotificationCenter.default.removeObserver(observer)
+        }
     }
 
     func updateCache() {