Workaround for GtkFileChooserButton bug: disable mouse wheel scrolling....

chrome/browser/gtk/options/advanced_contents_gtk.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/gtk/options/advanced_contents_gtk.h"
 
 #include <sys/types.h>
 #include <sys/wait.h>
 
 #include "app/l10n_util.h"
@@ skipping 40 matching lines @@
   return label;
 }
 
 GtkWidget* CreateCheckButtonWithWrappedLabel(int string_id) {
   GtkWidget* checkbox = gtk_check_button_new();
   gtk_container_add(GTK_CONTAINER(checkbox),
                     CreateWrappedLabel(string_id));
   return checkbox;
 }
 
+// Don't let the widget handle scroll events. Instead, pass it on to the
+// parent widget.
+gboolean PassScrollToParent(GtkWidget* widget, GdkEvent* event,
+                            gpointer unused) {
+  if (widget->parent)
+    gtk_propagate_event(widget->parent, event);
+
+  return TRUE;
+}
+
+// Recursively search for a combo box among the children of |widget|.
+void SearchForComboBox(GtkWidget* widget, gpointer data) {
+  if (GTK_IS_COMBO_BOX(widget)) {
+    *reinterpret_cast<GtkWidget**>(data) = widget;
+  } else if (GTK_IS_CONTAINER(widget)) {
+    gtk_container_foreach(GTK_CONTAINER(widget), SearchForComboBox, data);
+  }
+}
+
+// Letting the combo boxes in the advanced options page handle scroll events is
+// annoying because they fight with the scrolled window. Also,
+// GtkFileChooserButton is buggy in that if you scroll on it very quickly it
+// spews Gtk-WARNINGs, which causes us to crash in debug. This function disables
+// scrolling for the combo box in |widget| (the first one it finds in a DFS).
+void DisableScrolling(GtkWidget* widget) {
+  gpointer combo_box_ptr = NULL;
+  SearchForComboBox(widget, &combo_box_ptr);
+
+  if (!combo_box_ptr) {
+    NOTREACHED() << " Did not find a combo box in this widget.";
+    return;
+  }
+
+  g_signal_connect(GTK_WIDGET(combo_box_ptr), "scroll-event",
+                   G_CALLBACK(PassScrollToParent), NULL);
+}
+
 }  // anonymous namespace
 
 
 ///////////////////////////////////////////////////////////////////////////////
 // DownloadSection
 
 class DownloadSection : public OptionsPageBase {
  public:
   explicit DownloadSection(Profile* profile);
   virtual ~DownloadSection() {}
@@ skipping 39 matching lines @@
     : OptionsPageBase(profile), initializing_(true) {
   page_ = gtk_vbox_new(FALSE, gtk_util::kControlSpacing);
 
   // Download location options.
   download_location_button_ = gtk_file_chooser_button_new(
       l10n_util::GetStringUTF8(
           IDS_OPTIONS_DOWNLOADLOCATION_BROWSE_WINDOW_TITLE).c_str(),
       GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER);
   g_signal_connect(download_location_button_, "selection-changed",
                    G_CALLBACK(OnDownloadLocationChanged), this);
+  DisableScrolling(download_location_button_);
+
   // Add the default download path to the list of shortcuts in the selector.
   FilePath default_download_path;
   if (!PathService::Get(chrome::DIR_DEFAULT_DOWNLOADS,
                         &default_download_path)) {
     NOTREACHED();
   } else {
     if (!gtk_file_chooser_add_shortcut_folder(
         GTK_FILE_CHOOSER(download_location_button_),
         default_download_path.value().c_str(),
         NULL)) {
@@ skipping 333 matching lines @@
       l10n_util::GetStringUTF8(IDS_OPTIONS_COOKIES_ACCEPT_LABEL).c_str());
   gtk_misc_set_alignment(GTK_MISC(cookie_description_label), 0, 0);
   gtk_box_pack_start(GTK_BOX(page_), cookie_description_label, FALSE, FALSE, 0);
 
   GtkWidget* cookie_controls = gtk_vbox_new(FALSE, gtk_util::kControlSpacing);
   gtk_box_pack_start(GTK_BOX(page_),
                      OptionsLayoutBuilderGtk::IndentWidget(cookie_controls),
                      FALSE, FALSE, 0);
 
   cookie_behavior_combobox_ = gtk_combo_box_new_text();
+  DisableScrolling(cookie_behavior_combobox_);
   gtk_combo_box_append_text(
       GTK_COMBO_BOX(cookie_behavior_combobox_),
       l10n_util::GetStringUTF8(IDS_OPTIONS_COOKIES_ACCEPT_ALL_COOKIES).c_str());
   gtk_combo_box_append_text(
       GTK_COMBO_BOX(cookie_behavior_combobox_),
       l10n_util::GetStringUTF8(
           IDS_OPTIONS_COOKIES_RESTRICT_THIRD_PARTY_COOKIES).c_str());
   gtk_combo_box_append_text(
       GTK_COMBO_BOX(cookie_behavior_combobox_),
       l10n_util::GetStringUTF8(IDS_OPTIONS_COOKIES_BLOCK_ALL_COOKIES).c_str());
@@ skipping 364 matching lines @@
       l10n_util::GetStringUTF8(IDS_OPTIONS_ADVANCED_SECTION_TITLE_CONTENT),
       web_content_section_->get_page_widget(), false);
 
   security_section_.reset(new SecuritySection(profile_));
   options_builder.AddOptionGroup(
       l10n_util::GetStringUTF8(IDS_OPTIONS_ADVANCED_SECTION_TITLE_SECURITY),
       security_section_->get_page_widget(), false);
 
   page_ = options_builder.get_page_widget();
 }