Un-shared stage and its sublayers will appear as system lock

lib/usd/ui/layerEditor/layerEditorWidget.cpp

@@ -267,6 +267,12 @@ void LayerEditorWidget::updateButtons()
 {
     if (_sessionState.commandHook()->isProxyShapeSharedStage(
             _sessionState.stageEntry()._proxyShapePath)) {
+        if (_buttons._dirtyCountBadge) {
+            _buttons._dirtyCountBadge->setVisible(true);
+        }
+        if (_buttons._saveStageButton) {
+            _buttons._saveStageButton->setVisible(true);
+        }
         const auto layers = _treeView->layerTreeModel()->getAllNeedsSavingLayers();
         int        count = static_cast<int>(layers.size());
         for (auto layer : layers) {
@@ -284,6 +290,13 @@ void LayerEditorWidget::updateButtons()
         _buttons._dirtyCountBadge->updateCount(count);
         bool disable = count == 0;
         QtUtils::disableHIGButton(_buttons._saveStageButton, disable);
+    } else {
+        if (_buttons._dirtyCountBadge) {
+            _buttons._dirtyCountBadge->setVisible(false);
+        }
+        if (_buttons._saveStageButton) {
+            _buttons._saveStageButton->setVisible(false);
+        }
     }
     _updateButtonsOnIdle = false;
 }

lib/usd/ui/layerEditor/layerTreeItem.cpp

@@ -268,7 +268,7 @@ bool LayerTreeItem::sublayerOfShared() const
     return false;
 }
 
-bool LayerTreeItem::isReadOnly() const { return (_isSharedLayer); }
+bool LayerTreeItem::isReadOnly() const { return (_isSharedLayer) || sublayerOfShared(); }
 
 bool LayerTreeItem::isMovable() const
 {
@@ -293,7 +293,11 @@ bool LayerTreeItem::appearsLocked() const
     return false;
 }
 
-bool LayerTreeItem::isSystemLocked() const { return MayaUsd::isLayerSystemLocked(_layer); }
+bool LayerTreeItem::isSystemLocked() const
+{
+    // When a layer is being externally driven, it should appear as system-locked.
+    return MayaUsd::isLayerSystemLocked(_layer) || isReadOnly();
+}
 
 bool LayerTreeItem::appearsSystemLocked() const
 {

lib/usd/ui/layerEditor/layerTreeItem.h

@@ -133,7 +133,8 @@ class LayerTreeItem : public QStandardItem
     bool isMuted() const;
     // check if this layer is muted, or any of its parent
     bool appearsMuted() const;
-    // check if this layer is readonly
+    // check if this layer is readonly (whether it is a shared layer or a sublayer of a shared
+    // stage)
     bool isReadOnly() const;
     // true if dirty, but look at needsSaving for UI feedback
     bool isDirty() const { return _layer ? _layer->IsDirty() : false; }

lib/usd/ui/layerEditor/layerTreeItemDelegate.cpp

@@ -306,8 +306,10 @@ void LayerTreeItemDelegate::paint_drawOneAction(
     // MAYA 84884: Created a background rectangle underneath the icon to extend the mouse coverage
     // region
 
-    const bool     hover = QtUtils::isMouseInRectangle(_treeView, actionRect);
-    const bool     active = actionInfo._checked;
+    const bool hover = QtUtils::isMouseInRectangle(_treeView, actionRect);
+    bool       appearsChecked = actionAppearsChecked(actionInfo, ctx);
+    const bool active = appearsChecked;
+
     const QPixmap* icon = nullptr;
     if (hover) {
         icon = active ? &actionInfo._pixmap_on_hover : &actionInfo._pixmap_off_hover;
@@ -362,9 +364,11 @@ void LayerTreeItemDelegate::paint_ActionIcon(
     LayerActionInfo action;
     ctx.item->getActionButton(actionType, action);
 
+    bool appearsChecked = actionAppearsChecked(action, ctx);
+
     // Draw the icon if it is checked or if the mouse is over the item.
     const bool shouldDraw
-        = (action._checked || QtUtils::isMouseInRectangle(_treeView, ctx.itemRect));
+        = (appearsChecked || QtUtils::isMouseInRectangle(_treeView, ctx.itemRect));
     if (!shouldDraw)
         return;
 
@@ -389,6 +393,22 @@ void LayerTreeItemDelegate::paint_ActionIcons(QPainter* painter, const ItemPaint
     paint_ActionIcon(painter, ctx, LayerActionType::Mute);
 }
 
+bool LayerTreeItemDelegate::actionAppearsChecked(
+    const LayerActionInfo&  actionInfo,
+    const ItemPaintContext& ctx) const
+{
+    if (actionInfo._checked) {
+        return true;
+    }
+
+    // This is used to display un-sharable layers as system-locked
+    if (actionInfo._actionType == LayerActionType::Lock && ctx.isSystemLocked) {
+        return true;
+    }
+
+    return false;
+}
+
 void LayerTreeItemDelegate::paint(
     QPainter*                   painter,
     const QStyleOptionViewItem& option,

lib/usd/ui/layerEditor/layerTreeItemDelegate.h

@@ -157,6 +157,8 @@ class LayerTreeItemDelegate : public QStyledItemDelegate
         const LayerActionInfo&  action,
         const ItemPaintContext& ctx) const;
     void drawStdIcon(QPainter* painter, int left, int top, const QPixmap& pixmap) const;
+    // Returns true if an action should appear as checked on a layer tree item.
+    bool actionAppearsChecked(const LayerActionInfo& actionInfo, const ItemPaintContext& ctx) const;
 };
 
 } // namespace UsdLayerEditor