fix: per-group sentinel docks, editor inline-edit comment alignment

Sentinel dock refactored to per-tab-group model — each split group gets
its own hidden sentinel so tab bars stay visible without the Hide event
filter hack.  Editor inline-edit comment column now anchors correctly
for base-address edits and shows expression hint instead of generic text.

src/editor.cpp

@@ -2574,7 +2574,7 @@ bool RcxEditor::beginInlineEdit(EditTarget target, int line, int col) {
         m_editState.commentCol = cs.valid ? cs.start : -1;
         m_editState.lastValidationOk = true;  // original value is always valid
     } else if (target == EditTarget::BaseAddress) {
-        m_editState.commentCol = norm.end + 2;  // command row has no column layout
+        m_editState.commentCol = (int)lineText.size() + 2;  // after full command row content
     } else {
         m_editState.commentCol = -1;
     }
@@ -2590,8 +2590,9 @@ bool RcxEditor::beginInlineEdit(EditTarget target, int line, int col) {
     // (comment padding is no longer baked into every line to avoid unnecessary scroll width)
     if ((target == EditTarget::Value || target == EditTarget::BaseAddress)
         && m_editState.commentCol >= 0) {
-        int commentStart = norm.end + 2;
+        int commentStart = m_editState.commentCol;
-        int neededLen = commentStart + kColComment;
+        int commentWidth = (target == EditTarget::BaseAddress) ? 60 : kColComment;
+        int neededLen = commentStart + commentWidth;
         int currentLen = (int)lineText.size();
         if (currentLen < neededLen) {
             int extend = neededLen - currentLen;
@@ -3540,7 +3541,7 @@ void RcxEditor::setEditComment(const QString& comment) {
 
     // Place comment 2 spaces after current value, prefixed with //
     int valueEnd = editEndCol();
-    int startCol = valueEnd + 2;  // 2 spaces after value
+    int startCol = qMax(valueEnd + 2, m_editState.commentCol);
     int endCol = lineText.size();
     int availWidth = endCol - startCol;
     if (availWidth <= 0) { m_updatingComment = false; return; }
@@ -3589,7 +3590,12 @@ void RcxEditor::validateEditLive() {
     if (isValid) {
         m_sci->markerDelete(m_editState.line, M_ERR);
         if (isSelected) m_sci->markerAdd(m_editState.line, M_SELECTED);
-        if (stateChanged) setEditComment("Enter=Save Esc=Cancel");
+        if (stateChanged) {
+            if (m_editState.target == EditTarget::BaseAddress)
+                setEditComment(QStringLiteral("e.g. <mod.exe> + 0xFF | [0x1000 + 0x10] | 7ff6`1234ABCD"));
+            else
+                setEditComment("Enter=Save Esc=Cancel");
+        }
     } else {
         if (isSelected) m_sci->markerDelete(m_editState.line, M_SELECTED);
         m_sci->markerAdd(m_editState.line, M_ERR);

src/main.cpp

@@ -605,24 +605,6 @@ MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent) {
     createWorkspaceDock();
     createScannerDock();
 
-    // Hidden sentinel dock — never visible, only used to force Qt to create a
-    // QTabBar when the first document dock is added (Qt only creates tab bars
-    // via tabifyDockWidget).  Immediately hidden after tabification so it takes
-    // zero layout space.  An event filter on the QTabBar keeps it visible.
-    {
-        m_sentinelDock = new QDockWidget(this);
-        m_sentinelDock->setObjectName(QStringLiteral("_sentinel"));
-        m_sentinelDock->setFeatures(QDockWidget::NoDockWidgetFeatures);
-        auto* sw = new QWidget(m_sentinelDock);
-        sw->setFixedSize(0, 0);
-        m_sentinelDock->setWidget(sw);
-        auto* stb = new QWidget(m_sentinelDock);
-        stb->setFixedHeight(0);
-        m_sentinelDock->setTitleBarWidget(stb);
-        addDockWidget(Qt::TopDockWidgetArea, m_sentinelDock);
-        m_sentinelDock->hide();  // hidden = zero layout space
-    }
-
     createMenus();
     createStatusBar();
 
@@ -779,13 +761,22 @@ void MainWindow::createMenus() {
     // View
     auto* view = m_menuBar->addMenu("&View");
     Qt5Qt6AddAction(view, "&Reset Windows", QKeySequence::UnknownKey, QIcon(), this, [this](bool) {
-        // Re-tabify all doc docks into a single group
+        // Re-tabify all doc docks into a single group (collapses splits)
-        if (m_docDocks.size() < 2) return;
+        if (m_docDocks.isEmpty()) return;
         auto* first = m_docDocks.first();
         for (int i = 1; i < m_docDocks.size(); ++i) {
             tabifyDockWidget(first, m_docDocks[i]);
             m_docDocks[i]->show();
         }
+        // Merge all sentinels back; keep only the first, delete extras
+        for (int i = 0; i < m_sentinelDocks.size(); ++i) {
+            if (i == 0)
+                tabifyDockWidget(first, m_sentinelDocks[i]);
+            else
+                delete m_sentinelDocks[i];
+        }
+        if (m_sentinelDocks.size() > 1)
+            m_sentinelDocks.resize(1);
         if (m_activeDocDock) m_activeDocDock->raise();
         QTimer::singleShot(0, this, [this]() { setupDockTabBars(); });
     });
@@ -1538,6 +1529,21 @@ QString MainWindow::tabTitle(const TabState& tab) const {
     return name;
 }
 
+// Create a sentinel dock — invisible tab that keeps Qt's tab bar on-screen
+// when only 1 real dock remains in a group.
+QDockWidget* MainWindow::createSentinelDock() {
+    auto* sentinel = new QDockWidget(this);
+    sentinel->setObjectName(QStringLiteral("_sentinel_%1").arg(quintptr(sentinel), 0, 16));
+    sentinel->setFeatures(QDockWidget::NoDockWidgetFeatures);
+    sentinel->setWidget(new QWidget(sentinel));
+    auto* stb = new QWidget(sentinel);
+    stb->setFixedHeight(0);
+    sentinel->setTitleBarWidget(stb);
+    sentinel->setWindowTitle(QStringLiteral("\u200B"));
+    m_sentinelDocks.append(sentinel);
+    return sentinel;
+}
+
 QDockWidget* MainWindow::createTab(RcxDocument* doc) {
     auto* splitter = new QSplitter(Qt::Horizontal);
     splitter->setHandleWidth(1);
@@ -1658,19 +1664,22 @@ QDockWidget* MainWindow::createTab(RcxDocument* doc) {
     });
 
     // Tabify with existing doc docks, or add to top area
-    if (!m_docDocks.isEmpty())
+    if (!m_docDocks.isEmpty()) {
         tabifyDockWidget(m_docDocks.last(), dock);
-    else
+    } else {
         addDockWidget(Qt::TopDockWidgetArea, dock);
-
+        // Deferred sentinel — must wait for Qt to finish laying out the
-    // Bootstrap: tabify the hidden sentinel with the first doc dock so Qt
+        // first doc dock before tabifyDockWidget can merge them into tabs.
-    // creates a QTabBar.  Then hide sentinel (zero layout space).  The event
+        QTimer::singleShot(0, this, [this, dock]() {
-    // filter in eventFilter() keeps the tab bar visible even at count==1.
+            if (!dock->isVisible()) return;
-    if (m_sentinelDock && m_docDocks.isEmpty()) {
+            // Check if this dock already has a sentinel (e.g. second createTab raced)
-        m_sentinelDock->show();
+            for (auto* td : tabifiedDockWidgets(dock))
-        tabifyDockWidget(dock, m_sentinelDock);
+                if (m_sentinelDocks.contains(static_cast<QDockWidget*>(td))) return;
-        m_sentinelDock->hide();
+            auto* sentinel = createSentinelDock();
-        dock->raise();
+            tabifyDockWidget(dock, sentinel);
+            dock->raise();
+            setupDockTabBars();
+        });
     }
 
     m_docDocks.append(dock);
@@ -1908,11 +1917,19 @@ void MainWindow::setupDockTabBars() {
                 .arg(theme.background.name(), theme.border.name(), theme.hover.name()));
         }
 
-        // Force tab bar visible (event filter keeps it alive, belt-and-suspenders)
+        // Hide sentinel tabs so user sees only real doc tabs.
-        tabBar->show();
+        // Qt's updateTabBar() rebuilds tabs each layout pass, resetting
+        // visibility, so we must re-hide every call.
+        static const QString sentinelTitle = QStringLiteral("\u200B");
+        for (int i = 0; i < tabBar->count(); ++i) {
+            if (tabBar->tabText(i) == sentinelTitle)
+                tabBar->setTabVisible(i, false);
+        }
 
         // Install tab buttons for any tab that doesn't have them yet
         for (int i = 0; i < tabBar->count(); ++i) {
+            if (tabBar->tabText(i) == sentinelTitle)
+                continue;
             auto* existing = qobject_cast<DockTabButtons*>(
                 tabBar->tabButton(i, QTabBar::RightSide));
             if (existing) continue;
@@ -1996,8 +2013,11 @@ void MainWindow::setupDockTabBars() {
 
             menu.addSeparator();
 
-            // New Document Groups (only if >1 tab)
+            // New Document Groups (only if >1 visible tab — excludes sentinels)
-            if (tabBar->count() > 1) {
+            int visibleTabs = 0;
+            for (int i = 0; i < tabBar->count(); ++i)
+                if (tabBar->isTabVisible(i)) ++visibleTabs;
+            if (visibleTabs > 1) {
                 menu.addAction(makeIcon(":/vsicons/split-horizontal.svg"),
                                "New Horizontal Document Group",
                                [this, target]() {
@@ -2016,7 +2036,12 @@ void MainWindow::setupDockTabBars() {
                     }
                     if (docks.size() >= 2)
                         resizeDocks(docks, sizes, Qt::Horizontal);
-                    QTimer::singleShot(0, this, [this]() { setupDockTabBars(); });
+                    QTimer::singleShot(0, this, [this, target]() {
+                        auto* s = createSentinelDock();
+                        tabifyDockWidget(target, s);
+                        target->raise();
+                        QTimer::singleShot(0, this, [this]() { setupDockTabBars(); });
+                    });
                 });
                 menu.addAction(makeIcon(":/vsicons/split-vertical.svg"),
                                "New Vertical Document Group",
@@ -2036,7 +2061,12 @@ void MainWindow::setupDockTabBars() {
                     }
                     if (docks.size() >= 2)
                         resizeDocks(docks, sizes, Qt::Vertical);
-                    QTimer::singleShot(0, this, [this]() { setupDockTabBars(); });
+                    QTimer::singleShot(0, this, [this, target]() {
+                        auto* s = createSentinelDock();
+                        tabifyDockWidget(target, s);
+                        target->raise();
+                        QTimer::singleShot(0, this, [this]() { setupDockTabBars(); });
+                    });
                 });
             }
 
@@ -2046,25 +2076,6 @@ void MainWindow::setupDockTabBars() {
 }
 
 bool MainWindow::eventFilter(QObject* obj, QEvent* event) {
-    // Keep dock tab bars visible even when Qt wants to hide them (count==1).
-    // Qt's QMainWindowLayout calls setVisible(false) on the QTabBar when only
-    // one dock remains in a tab group.  We catch the resulting Hide event and
-    // immediately re-show the tab bar, provided at least one doc dock is docked.
-    if (event->type() == QEvent::Hide && !m_tabBarShowGuard) {
-        if (auto* tabBar = qobject_cast<QTabBar*>(obj)) {
-            if (tabBar->parent() == this && tabBar->count() >= 1) {
-                bool hasDockedDoc = false;
-                for (auto* d : m_docDocks)
-                    if (!d->isFloating() && d->isVisible()) { hasDockedDoc = true; break; }
-                if (hasDockedDoc) {
-                    m_tabBarShowGuard = true;
-                    tabBar->show();
-                    m_tabBarShowGuard = false;
-                    return true;
-                }
-            }
-        }
-    }
     if (event->type() == QEvent::MouseButtonPress) {
         auto* me = static_cast<QMouseEvent*>(event);
         if (me->button() == Qt::MiddleButton) {

src/mainwindow.h

@@ -120,10 +120,9 @@ private:
     QMap<QDockWidget*, TabState> m_tabs;
     QVector<QDockWidget*> m_docDocks;       // ordered list for tabByIndex
     QDockWidget* m_activeDocDock = nullptr;  // tracks active document dock
-    QDockWidget* m_sentinelDock  = nullptr;  // hidden dock to bootstrap tab bar creation
+    QVector<QDockWidget*> m_sentinelDocks;    // permanent sentinels for always-visible tab bars
     QVector<RcxDocument*> m_allDocs;  // all open docs, shared with controllers
     bool m_closingAll = false;        // guards spurious project_new during batch close
-    bool m_tabBarShowGuard = false;   // prevents recursion in event filter re-show
     struct ClosingGuard {
         bool& flag;
         ClosingGuard(bool& f) : flag(f) { flag = true; }
@@ -144,6 +143,7 @@ private:
     TabState* activeTab();
     TabState* tabByIndex(int index);
     int tabCount() const { return m_tabs.size(); }
+    QDockWidget* createSentinelDock();
     QDockWidget* createTab(RcxDocument* doc);
     QString tabTitle(const TabState& tab) const;
     void setupDockTabBars();