Fix help banner visibility

- Show banner on showEvent (when flow view becomes visible)
- Show banner on mouse enter event
- Raise banner to front to ensure visibility
- Recalculate size before positioning

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/cmdforge/gui/widgets/flow_graph.py

@@ -317,28 +317,41 @@ class FlowGraphWidget(QWidget):
         else:
             super().keyPressEvent(event)
 
+    def showEvent(self, event):
+        """Handle widget becoming visible."""
+        super().showEvent(event)
+        # Show help banner when flow view becomes visible
+        QTimer.singleShot(100, self._show_help_banner)
+
     def eventFilter(self, obj, event):
         """Filter events from the graph widget to catch F key and focus."""
         if event.type() == QEvent.KeyPress and event.key() == Qt.Key_F:
             self.fit_all_nodes()
             return True  # Event handled
-        elif event.type() == QEvent.FocusIn:
+        elif event.type() == QEvent.Enter:
+            # Show banner when mouse enters the graph area
             self._show_help_banner()
         return super().eventFilter(obj, event)
 
     def _show_help_banner(self):
         """Show the help banner with fade effect."""
-        if not self._help_banner:
+        if not self._help_banner or not self._graph:
             return
 
+        # Make sure size is calculated
+        self._help_banner.adjustSize()
+
         # Position at top center of the graph widget
         parent_width = self._graph.widget.width()
         banner_width = self._help_banner.width()
-        x = (parent_width - banner_width) // 2
+        x = max(10, (parent_width - banner_width) // 2)
         self._help_banner.move(x, 10)
 
-        # Show and start auto-hide timer
+        # Raise to front and show
+        self._help_banner.raise_()
         self._help_banner.show()
+
+        # Start auto-hide timer
         self._hide_timer.start(3000)  # Hide after 3 seconds
 
     def _fade_out_banner(self):