Created attachment 349013 [details] [review]
flowbox: don’t try to focus or draw NULL widgets

most callers seem to avoid calling gtk_flow_box_update_cursor (..., NULL)

can you show a stacktrace from where that call originates ?

+ Trace 237303

I’m reproducing by changing the selection mode to multiple in the selection dialog in the widget factory demo, but it’s more a problem in Nautilus with the new flow view.

Here is an alternative patch, which should be slightly more correct.
Does this work for you ?


diff --git a/gtk/gtkflowbox.c b/gtk/gtkflowbox.c
index d443047c96..2ad1d487ff 100644
--- a/gtk/gtkflowbox.c
+++ b/gtk/gtkflowbox.c
@@ -2808,7 +2808,8 @@ gtk_flow_box_drag_gesture_update (GtkGestureDrag *gesture,
       g_object_unref (priv->rubberband_node);
 
       /* Grab focus here, so Escape-to-stop-rubberband  works */
-      gtk_flow_box_update_cursor (box, priv->rubberband_first);
+      if (priv->rubberband_first)
+        gtk_flow_box_update_cursor (box, priv->rubberband_first);
       gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_CLAIMED);
     }
 
@@ -2818,7 +2819,11 @@ gtk_flow_box_drag_gesture_update (GtkGestureDrag *gesture,
                                               start_y + offset_y);
 
       if (priv->rubberband_first == NULL)
-        priv->rubberband_first = child;
+        {
+          priv->rubberband_first = child;
+          if (priv->rubberband_first)
+            gtk_flow_box_update_cursor (box, priv->rubberband_first);
+        }
       if (child != NULL)
         priv->rubberband_last = child;

(In reply to Matthias Clasen from comment #5)
> Here is an alternative patch, which should be slightly more correct.
> Does this work for you ?

Yup, does the trick.

Attachment 349013 [details] pushed as 7860e2d - flowbox: don’t try to focus or draw NULL widgets