Bug 795471 - Budget window scrolls edited cell out of site

When editing cells that have been revealed on the right by scrolling the
window snaps back to the left hiding the cell being edited. This may be
due to an underlying gtk issue but these changes fix the issue visually.

gnucash/gnome/gnc-budget-view.c

@@ -133,6 +133,8 @@ static gnc_numeric gbv_get_accumulated_budget_amount(GncBudget* budget,
     This structure defines the different elements required for a budget view - the actual display of how a budget looks when you open it.
         @param tree_view Pointer to the widget to display the detailed budget.
         @param totals_tree_view Pointer to the widget to display the totals tree at the bottom of the budget screen.
+        @param the main scrolled window horizonatl adjustment
+        @param saved value for the horizontal adjustment
         @param budget Contains much of the data required to implement a budget.
         @param key Each budget struct has its own GUID.
         @param period_col_list List of columns in the tree_view widget (this list varies depending on the number of periods)
@@ -145,6 +147,9 @@ struct GncBudgetViewPrivate
     GtkTreeView *tree_view;
     GtkTreeView *totals_tree_view;
 
+    GtkAdjustment *hadj;
+    gfloat hadj_value;
+
     GncBudget* budget;
     GncGUID key;
 
@@ -312,6 +317,32 @@ gnc_budget_view_get_selected_accounts(GncBudgetView* view)
     return gnc_tree_view_account_get_selected_accounts(GNC_TREE_VIEW_ACCOUNT(priv->tree_view));
 }
 
+static void
+gbv_container_set_focus_child_cb(GtkContainer *container, GtkWidget *widget,
+                               GncBudgetView* view)
+{
+    GncBudgetViewPrivate *priv;
+    g_return_if_fail(GNC_IS_BUDGET_VIEW(view));
+
+    priv = GNC_BUDGET_VIEW_GET_PRIVATE(view);
+
+    PINFO("set-focus-child container is %p, widget is %p", container, widget);
+
+    /* There seems to be an underlying gtk issue in this configuration when
+     * the main scroll window is scrolled to reveal the cells on the right
+     * and once selected/focused the window snapps back to the left so
+     * you can no longer see the cell. By saving the horizontal adjustment
+     * value from when this callback is called for inner_scrolled_window
+     * and using it when the main scrolled windows calls this call back
+     * visualy stops the error.
+     */
+
+    if (widget == GTK_WIDGET(priv->tree_view)) // we are looking at the inner scrolled window
+        priv->hadj_value = gtk_adjustment_get_value(priv->hadj);
+    else // we are looking at the scrolled window
+        gtk_adjustment_set_value(priv->hadj, priv->hadj_value);
+}
+
 /****************************
  * GncPluginPage Functions  *
  ***************************/
@@ -350,6 +381,9 @@ gbv_create_widget(GncBudgetView *view)
     gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scrolled_window),
                                    GTK_POLICY_AUTOMATIC,
                                    GTK_POLICY_NEVER);
+    // save the main scrolled window horizontal adjustment
+    priv->hadj = gtk_scrolled_window_get_hadjustment(GTK_SCROLLED_WINDOW(scrolled_window));
+
     gtk_widget_show(scrolled_window);
     gtk_box_pack_start(GTK_BOX(vbox), scrolled_window, /*expand*/TRUE, /*fill*/TRUE, 0);
 
@@ -358,6 +392,10 @@ gbv_create_widget(GncBudgetView *view)
     gtk_container_add (GTK_CONTAINER(scrolled_window), GTK_WIDGET(inner_vbox));
     gtk_widget_show(GTK_WIDGET(inner_vbox));
 
+    // This is used to keep the selected cell in view
+    g_signal_connect(G_OBJECT(scrolled_window), "set-focus-child",
+                     G_CALLBACK(gbv_container_set_focus_child_cb), view);
+
     inner_scrolled_window = gtk_scrolled_window_new(NULL, NULL);
     gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(inner_scrolled_window),
                                    GTK_POLICY_NEVER,
@@ -366,6 +404,10 @@ gbv_create_widget(GncBudgetView *view)
     tree_view = gnc_tree_view_account_new(FALSE);
     gtk_container_add(GTK_CONTAINER(inner_scrolled_window), GTK_WIDGET(tree_view));
 
+    // This is used to keep the selected cell in view
+    g_signal_connect(G_OBJECT(inner_scrolled_window), "set-focus-child",
+                     G_CALLBACK(gbv_container_set_focus_child_cb), view);
+
     guid_to_string_buff(&priv->key, guidstr);
     state_section = g_strjoin(" ", STATE_SECTION_PREFIX, guidstr, NULL);
     g_object_set(G_OBJECT(tree_view), "state-section", state_section, NULL);