diff --git a/src/gui_gtk_f.c b/src/gui_gtk_f.c
index 0eb5065..838a4ca 100644
--- a/src/gui_gtk_f.c
+++ b/src/gui_gtk_f.c
@@ -19,13 +19,19 @@
  * children at arbitrary positions width arbitrary sizes.  This finally puts
  * an end on our resize problems with which we where struggling for such a
  * long time.
+ *
+ * Support for GTK+ 3 was added by:
+ *
+ * 2016  Kazunobu Kuriyama  <kazunobu.kuriyama@gmail.com>
  */
 
 #include "vim.h"
 #include <gtk/gtk.h>	/* without this it compiles, but gives errors at
 			   runtime! */
 #include "gui_gtk_f.h"
-#include <gtk/gtksignal.h>
+#if !GTK_CHECK_VERSION(3,0,0)
+# include <gtk/gtksignal.h>
+#endif
 #ifdef WIN3264
 # include <gdk/gdkwin32.h>
 #else
@@ -52,10 +58,23 @@
 static void gtk_form_map(GtkWidget *widget);
 static void gtk_form_size_request(GtkWidget *widget,
 				  GtkRequisition *requisition);
+#if GTK_CHECK_VERSION(3,0,0)
+static void gtk_form_get_preferred_width(GtkWidget *widget,
+					 gint *minimal_width,
+					 gint *natural_width);
+static void gtk_form_get_preferred_height(GtkWidget *widget,
+					  gint *minimal_height,
+					  gint *natural_height);
+#endif
 static void gtk_form_size_allocate(GtkWidget *widget,
 				   GtkAllocation *allocation);
+#if GTK_CHECK_VERSION(3,0,0)
+static gboolean gtk_form_draw(GtkWidget *widget,
+			      cairo_t *cr);
+#else
 static gint gtk_form_expose(GtkWidget *widget,
 			    GdkEventExpose *event);
+#endif
 
 static void gtk_form_remove(GtkContainer *container,
 			    GtkWidget *widget);
@@ -73,22 +92,27 @@
 				    gboolean force_allocate);
 static void gtk_form_position_children(GtkForm *form);
 
+#if !GTK_CHECK_VERSION(3,0,0)
 static GdkFilterReturn gtk_form_filter(GdkXEvent *gdk_xevent,
 				       GdkEvent *event,
 				       gpointer data);
 static GdkFilterReturn gtk_form_main_filter(GdkXEvent *gdk_xevent,
 					    GdkEvent *event,
 					    gpointer data);
-
+#endif
+#if !GTK_CHECK_VERSION(3,16,0)
 static void gtk_form_set_static_gravity(GdkWindow *window,
 					gboolean use_static);
+#endif
 
 static void gtk_form_send_configure(GtkForm *form);
 
 static void gtk_form_child_map(GtkWidget *widget, gpointer user_data);
 static void gtk_form_child_unmap(GtkWidget *widget, gpointer user_data);
 
+#if !GTK_CHECK_VERSION(3,0,0)
 static GtkWidgetClass *parent_class = NULL;
+#endif
 
 /* Public interface
  */
@@ -98,7 +122,11 @@
 {
     GtkForm *form;
 
+#if GTK_CHECK_VERSION(3,0,0)
+    form = g_object_new(GTK_TYPE_FORM, NULL);
+#else
     form = gtk_type_new(gtk_form_get_type());
+#endif
 
     return GTK_WIDGET(form);
 }
@@ -120,8 +148,12 @@
     child->window = NULL;
     child->x = x;
     child->y = y;
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_set_size_request(child->widget, -1, -1);
+#else
     child->widget->requisition.width = 0;
     child->widget->requisition.height = 0;
+#endif
     child->mapped = FALSE;
 
     form->children = g_list_append(form->children, child);
@@ -131,13 +163,24 @@
      * that gtk_widget_set_parent() realizes the widget if it's visible
      * and its parent is mapped.
      */
+#if GTK_CHECK_VERSION(3,0,0)
+    if (gtk_widget_get_realized(GTK_WIDGET(form)))
+#else
     if (GTK_WIDGET_REALIZED(form))
+#endif
 	gtk_form_attach_child_window(form, child);
 
     gtk_widget_set_parent(child_widget, GTK_WIDGET(form));
+#if !GTK_CHECK_VERSION(3,0,0)
     gtk_widget_size_request(child->widget, NULL);
+#endif
 
+#if GTK_CHECK_VERSION(3,0,0)
+    if (gtk_widget_get_realized(GTK_WIDGET(form))
+	    && !gtk_widget_get_realized(child_widget))
+#else
     if (GTK_WIDGET_REALIZED(form) && !GTK_WIDGET_REALIZED(child_widget))
+#endif
 	gtk_form_realize_child(form, child);
 
     gtk_form_position_child(form, child, TRUE);
@@ -193,6 +236,9 @@
 
 /* Basic Object handling procedures
  */
+#if GTK_CHECK_VERSION(3,0,0)
+G_DEFINE_TYPE(GtkForm, gtk_form, GTK_TYPE_CONTAINER)
+#else
     GtkType
 gtk_form_get_type(void)
 {
@@ -213,6 +259,7 @@
     }
     return form_type;
 }
+#endif /* !GTK_CHECK_VERSION(3,0,0) */
 
     static void
 gtk_form_class_init(GtkFormClass *klass)
@@ -223,14 +270,25 @@
     widget_class = (GtkWidgetClass *) klass;
     container_class = (GtkContainerClass *) klass;
 
+#if !GTK_CHECK_VERSION(3,0,0)
     parent_class = gtk_type_class(gtk_container_get_type());
+#endif
 
     widget_class->realize = gtk_form_realize;
     widget_class->unrealize = gtk_form_unrealize;
     widget_class->map = gtk_form_map;
+#if GTK_CHECK_VERSION(3,0,0)
+    widget_class->get_preferred_width = gtk_form_get_preferred_width;
+    widget_class->get_preferred_height = gtk_form_get_preferred_height;
+#else
     widget_class->size_request = gtk_form_size_request;
+#endif
     widget_class->size_allocate = gtk_form_size_allocate;
+#if GTK_CHECK_VERSION(3,0,0)
+    widget_class->draw = gtk_form_draw;
+#else
     widget_class->expose_event = gtk_form_expose;
+#endif
 
     container_class->remove = gtk_form_remove;
     container_class->forall = gtk_form_forall;
@@ -239,15 +297,22 @@
     static void
 gtk_form_init(GtkForm *form)
 {
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_set_has_window(GTK_WIDGET(form), TRUE);
+#endif
     form->children = NULL;
 
+#if !GTK_CHECK_VERSION(3,0,0)
     form->width = 1;
     form->height = 1;
+#endif
 
     form->bin_window = NULL;
 
+#if !GTK_CHECK_VERSION(3,0,0)
     form->configure_serial = 0;
     form->visibility = GDK_VISIBILITY_PARTIAL;
+#endif
 
     form->freeze_count = 0;
 }
@@ -267,40 +332,92 @@
     g_return_if_fail(GTK_IS_FORM(widget));
 
     form = GTK_FORM(widget);
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_set_realized(widget, TRUE);
+#else
     GTK_WIDGET_SET_FLAGS(form, GTK_REALIZED);
+#endif
 
     attributes.window_type = GDK_WINDOW_CHILD;
+#if GTK_CHECK_VERSION(3,0,0)
+    {
+	GtkAllocation allocation;
+	gtk_widget_get_allocation(widget, &allocation);
+	attributes.x = allocation.x;
+	attributes.y = allocation.y;
+	attributes.width = allocation.width;
+	attributes.height = allocation.height;
+    }
+#else
     attributes.x = widget->allocation.x;
     attributes.y = widget->allocation.y;
     attributes.width = widget->allocation.width;
     attributes.height = widget->allocation.height;
+#endif
     attributes.wclass = GDK_INPUT_OUTPUT;
     attributes.visual = gtk_widget_get_visual(widget);
+#if GTK_CHECK_VERSION(3,0,0)
+    attributes.event_mask = GDK_EXPOSURE_MASK;
+#else
     attributes.colormap = gtk_widget_get_colormap(widget);
     attributes.event_mask = GDK_VISIBILITY_NOTIFY_MASK;
+#endif
 
+#if GTK_CHECK_VERSION(3,0,0)
+    attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL;
+#else
     attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;
+#endif
 
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_set_window(widget,
+			  gdk_window_new(gtk_widget_get_parent_window(widget),
+					 &attributes, attributes_mask));
+    gdk_window_set_user_data(gtk_widget_get_window(widget), widget);
+#else
     widget->window = gdk_window_new(gtk_widget_get_parent_window(widget),
 				    &attributes, attributes_mask);
     gdk_window_set_user_data(widget->window, widget);
+#endif
 
     attributes.x = 0;
     attributes.y = 0;
     attributes.event_mask = gtk_widget_get_events(widget);
 
+#if GTK_CHECK_VERSION(3,0,0)
+    form->bin_window = gdk_window_new(gtk_widget_get_window(widget),
+				      &attributes, attributes_mask);
+#else
     form->bin_window = gdk_window_new(widget->window,
 				      &attributes, attributes_mask);
+#endif
     gdk_window_set_user_data(form->bin_window, widget);
 
+#if !GTK_CHECK_VERSION(3,16,0)
     gtk_form_set_static_gravity(form->bin_window, TRUE);
+#endif
 
+#if GTK_CHECK_VERSION(3,0,0)
+    {
+	GtkStyleContext * const sctx = gtk_widget_get_style_context(widget);
+
+	gtk_style_context_add_class(sctx, "gtk-form");
+	gtk_style_context_set_state(sctx, GTK_STATE_FLAG_NORMAL);
+# if !GTK_CHECK_VERSION(3,18,0)
+	gtk_style_context_set_background(sctx, gtk_widget_get_window(widget));
+	gtk_style_context_set_background(sctx, form->bin_window);
+# endif
+    }
+#else
     widget->style = gtk_style_attach(widget->style, widget->window);
     gtk_style_set_background(widget->style, widget->window, GTK_STATE_NORMAL);
     gtk_style_set_background(widget->style, form->bin_window, GTK_STATE_NORMAL);
+#endif
 
+#if !GTK_CHECK_VERSION(3,0,0)
     gdk_window_add_filter(widget->window, gtk_form_main_filter, form);
     gdk_window_add_filter(form->bin_window, gtk_form_filter, form);
+#endif
 
     for (tmp_list = form->children; tmp_list; tmp_list = tmp_list->next)
     {
@@ -308,7 +425,11 @@
 
 	gtk_form_attach_child_window(form, child);
 
+#if GTK_CHECK_VERSION(3,0,0)
+	if (gtk_widget_get_visible(child->widget))
+#else
 	if (GTK_WIDGET_VISIBLE(child->widget))
+#endif
 	    gtk_form_realize_child(form, child);
     }
 }
@@ -332,17 +453,30 @@
 
     form = GTK_FORM(widget);
 
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_set_mapped(widget, TRUE);
+#else
     GTK_WIDGET_SET_FLAGS(widget, GTK_MAPPED);
+#endif
 
+#if GTK_CHECK_VERSION(3,0,0)
+    gdk_window_show(gtk_widget_get_window(widget));
+#else
     gdk_window_show(widget->window);
+#endif
     gdk_window_show(form->bin_window);
 
     for (tmp_list = form->children; tmp_list; tmp_list = tmp_list->next)
     {
 	GtkFormChild *child = tmp_list->data;
 
+#if GTK_CHECK_VERSION(3,0,0)
+	if (gtk_widget_get_visible(child->widget)
+		&& !gtk_widget_get_mapped(child->widget))
+#else
 	if (GTK_WIDGET_VISIBLE(child->widget)
 		&& !GTK_WIDGET_MAPPED(child->widget))
+#endif
 	    gtk_widget_map(child->widget);
     }
 }
@@ -369,12 +503,21 @@
 
 	if (child->window != NULL)
 	{
+#if GTK_CHECK_VERSION(3,0,0)
+	    g_signal_handlers_disconnect_by_func(G_OBJECT(child->widget),
+		    G_CALLBACK(gtk_form_child_map),
+		    child);
+	    g_signal_handlers_disconnect_by_func(G_OBJECT(child->widget),
+		    G_CALLBACK(gtk_form_child_unmap),
+		    child);
+#else
 	    gtk_signal_disconnect_by_func(GTK_OBJECT(child->widget),
 					  GTK_SIGNAL_FUNC(gtk_form_child_map),
 					  child);
 	    gtk_signal_disconnect_by_func(GTK_OBJECT(child->widget),
 					  GTK_SIGNAL_FUNC(gtk_form_child_unmap),
 					  child);
+#endif
 
 	    gdk_window_set_user_data(child->window, NULL);
 	    gdk_window_destroy(child->window);
@@ -385,20 +528,33 @@
 	tmp_list = tmp_list->next;
     }
 
+#if GTK_CHECK_VERSION(3,0,0)
+    if (GTK_WIDGET_CLASS (gtk_form_parent_class)->unrealize)
+	 (* GTK_WIDGET_CLASS (gtk_form_parent_class)->unrealize) (widget);
+#else
     if (GTK_WIDGET_CLASS (parent_class)->unrealize)
 	 (* GTK_WIDGET_CLASS (parent_class)->unrealize) (widget);
+#endif
 }
 
     static void
 gtk_form_size_request(GtkWidget *widget, GtkRequisition *requisition)
 {
+#if !GTK_CHECK_VERSION(3,0,0)
     GList *tmp_list;
     GtkForm *form;
+#endif
 
     g_return_if_fail(GTK_IS_FORM(widget));
 
+#if !GTK_CHECK_VERSION(3,0,0)
     form = GTK_FORM(widget);
+#endif
 
+#if GTK_CHECK_VERSION(3,0,0)
+    requisition->width = 1;
+    requisition->height = 1;
+#else
     requisition->width = form->width;
     requisition->height = form->height;
 
@@ -410,25 +566,71 @@
 	gtk_widget_size_request(child->widget, NULL);
 	tmp_list = tmp_list->next;
     }
+#endif
 }
 
+#if GTK_CHECK_VERSION(3,0,0)
+    static void
+gtk_form_get_preferred_width(GtkWidget *widget,
+			     gint      *minimal_width,
+			     gint      *natural_width)
+{
+    GtkRequisition requisition;
+
+    gtk_form_size_request(widget, &requisition);
+
+    *minimal_width = requisition.width;
+    *natural_width = requisition.width;
+}
+
+    static void
+gtk_form_get_preferred_height(GtkWidget *widget,
+			      gint	*minimal_height,
+			      gint	*natural_height)
+{
+    GtkRequisition requisition;
+
+    gtk_form_size_request(widget, &requisition);
+
+    *minimal_height = requisition.height;
+    *natural_height = requisition.height;
+}
+#endif /* GTK_CHECK_VERSION(3,0,0) */
+
     static void
 gtk_form_size_allocate(GtkWidget *widget, GtkAllocation *allocation)
 {
     GList *tmp_list;
     GtkForm *form;
     gboolean need_reposition;
+#if GTK_CHECK_VERSION(3,0,0)
+    GtkAllocation cur_alloc;
+#endif
 
     g_return_if_fail(GTK_IS_FORM(widget));
 
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_get_allocation(widget, &cur_alloc);
+
+    if (cur_alloc.x == allocation->x
+	    && cur_alloc.y == allocation->y
+	    && cur_alloc.width == allocation->width
+	    && cur_alloc.height == allocation->height)
+#else
     if (widget->allocation.x == allocation->x
 	    && widget->allocation.y == allocation->y
 	    && widget->allocation.width == allocation->width
 	    && widget->allocation.height == allocation->height)
+#endif
 	return;
 
+#if GTK_CHECK_VERSION(3,0,0)
+    need_reposition = cur_alloc.width != allocation->width
+		   || cur_alloc.height != allocation->height;
+#else
     need_reposition = widget->allocation.width != allocation->width
 		   || widget->allocation.height != allocation->height;
+#endif
     form = GTK_FORM(widget);
 
     if (need_reposition)
@@ -444,20 +646,81 @@
 	}
     }
 
+#if GTK_CHECK_VERSION(3,0,0)
+    if (gtk_widget_get_realized(widget))
+#else
     if (GTK_WIDGET_REALIZED(widget))
+#endif
     {
+#if GTK_CHECK_VERSION(3,0,0)
+	gdk_window_move_resize(gtk_widget_get_window(widget),
+			       allocation->x, allocation->y,
+			       allocation->width, allocation->height);
+#else
 	gdk_window_move_resize(widget->window,
 			       allocation->x, allocation->y,
 			       allocation->width, allocation->height);
+#endif
 	gdk_window_move_resize(GTK_FORM(widget)->bin_window,
 			       0, 0,
 			       allocation->width, allocation->height);
     }
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_set_allocation(widget, allocation);
+#else
     widget->allocation = *allocation;
+#endif
     if (need_reposition)
 	gtk_form_send_configure(form);
 }
 
+#if GTK_CHECK_VERSION(3,0,0)
+    static void
+gtk_form_render_background(GtkWidget *widget, cairo_t *cr)
+{
+    gtk_render_background(gtk_widget_get_style_context(widget), cr,
+			  0, 0,
+			  gtk_widget_get_allocated_width(widget),
+			  gtk_widget_get_allocated_height(widget));
+}
+
+    static gboolean
+gtk_form_draw(GtkWidget *widget, cairo_t *cr)
+{
+    GList   *tmp_list = NULL;
+    GtkForm *form     = NULL;
+
+    g_return_val_if_fail(GTK_IS_FORM(widget), FALSE);
+
+    gtk_form_render_background(widget, cr);
+
+    form = GTK_FORM(widget);
+    for (tmp_list = form->children; tmp_list; tmp_list = tmp_list->next)
+    {
+	GtkFormChild * const formchild = tmp_list->data;
+
+	if (!gtk_widget_get_has_window(formchild->widget) &&
+		gtk_cairo_should_draw_window(cr, formchild->window))
+	{
+	    /* To get gtk_widget_draw() to work, it is required to call
+	     * gtk_widget_size_allocate() in advance with a well-posed
+	     * allocation for a given child widget in order to set a
+	     * certain private GtkWidget variable, called
+	     * widget->priv->alloc_need, to the proper value; othewise,
+	     * gtk_widget_draw() fails and the relevant scrollbar won't
+	     * appear on the screen.
+	     *
+	     * Calling gtk_form_position_child() like this is one of ways
+	     * to make sure of that. */
+	    gtk_form_position_child(form, formchild, TRUE);
+
+	    gtk_form_render_background(formchild->widget, cr);
+	}
+    }
+
+    return GTK_WIDGET_CLASS(gtk_form_parent_class)->draw(widget, cr);
+}
+#else /* !GTK_CHECK_VERSION(3,0,0) */
     static gint
 gtk_form_expose(GtkWidget *widget, GdkEventExpose *event)
 {
@@ -497,6 +760,7 @@
 
     return FALSE;
 }
+#endif /* !GTK_CHECK_VERSION(3,0,0) */
 
 /* Container method
  */
@@ -522,12 +786,22 @@
 
     if (tmp_list)
     {
+#if GTK_CHECK_VERSION(3,0,0)
+	const gboolean was_visible = gtk_widget_get_visible(widget);
+#endif
 	if (child->window)
 	{
+#if GTK_CHECK_VERSION(3,0,0)
+	    g_signal_handlers_disconnect_by_func(G_OBJECT(child->widget),
+					  G_CALLBACK(&gtk_form_child_map), child);
+	    g_signal_handlers_disconnect_by_func(G_OBJECT(child->widget),
+					  G_CALLBACK(&gtk_form_child_unmap), child);
+#else
 	    gtk_signal_disconnect_by_func(GTK_OBJECT(child->widget),
 					  GTK_SIGNAL_FUNC(&gtk_form_child_map), child);
 	    gtk_signal_disconnect_by_func(GTK_OBJECT(child->widget),
 					  GTK_SIGNAL_FUNC(&gtk_form_child_unmap), child);
+#endif
 
 	    /* FIXME: This will cause problems for reparenting NO_WINDOW
 	     * widgets out of a GtkForm
@@ -536,7 +810,10 @@
 	    gdk_window_destroy(child->window);
 	}
 	gtk_widget_unparent(widget);
-
+#if GTK_CHECK_VERSION(3,0,0)
+	if (was_visible)
+	    gtk_widget_queue_resize(GTK_WIDGET(container));
+#endif
 	form->children = g_list_remove_link(form->children, tmp_list);
 	g_list_free_1(tmp_list);
 	g_free(child);
@@ -577,7 +854,11 @@
     if (child->window != NULL)
 	return; /* been there, done that */
 
+#if GTK_CHECK_VERSION(3,0,0)
+    if (!gtk_widget_get_has_window(child->widget))
+#else
     if (GTK_WIDGET_NO_WINDOW(child->widget))
+#endif
     {
 	GtkWidget	*widget;
 	GdkWindowAttr	attributes;
@@ -588,34 +869,75 @@
 	attributes.window_type = GDK_WINDOW_CHILD;
 	attributes.x = child->x;
 	attributes.y = child->y;
+#if GTK_CHECK_VERSION(3,0,0)
+	{
+	    GtkRequisition requisition;
+
+	    gtk_widget_get_preferred_size(child->widget, &requisition, NULL);
+
+	    attributes.width = requisition.width;
+	    attributes.height = requisition.height;
+	}
+#else
 	attributes.width = child->widget->requisition.width;
 	attributes.height = child->widget->requisition.height;
+#endif
 	attributes.wclass = GDK_INPUT_OUTPUT;
 	attributes.visual = gtk_widget_get_visual(widget);
+#if !GTK_CHECK_VERSION(3,0,0)
 	attributes.colormap = gtk_widget_get_colormap(widget);
+#endif
 	attributes.event_mask = GDK_EXPOSURE_MASK;
 
+#if GTK_CHECK_VERSION(3,0,0)
+	attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL;
+#else
 	attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;
+#endif
 	child->window = gdk_window_new(form->bin_window,
 				       &attributes, attributes_mask);
 	gdk_window_set_user_data(child->window, widget);
 
+#if GTK_CHECK_VERSION(3,0,0)
+	{
+	    GtkStyleContext * const sctx = gtk_widget_get_style_context(widget);
+
+	    gtk_style_context_set_state(sctx, GTK_STATE_FLAG_NORMAL);
+# if !GTK_CHECK_VERSION(3,18,0)
+	    gtk_style_context_set_background(sctx, child->window);
+# endif
+	}
+#else
 	gtk_style_set_background(widget->style,
 				 child->window,
 				 GTK_STATE_NORMAL);
+#endif
 
 	gtk_widget_set_parent_window(child->widget, child->window);
+#if !GTK_CHECK_VERSION(3,16,0)
 	gtk_form_set_static_gravity(child->window, TRUE);
+#endif
 	/*
 	 * Install signal handlers to map/unmap child->window
 	 * alongside with the actual widget.
 	 */
+#if GTK_CHECK_VERSION(3,0,0)
+	g_signal_connect(G_OBJECT(child->widget), "map",
+			 G_CALLBACK(&gtk_form_child_map), child);
+	g_signal_connect(G_OBJECT(child->widget), "unmap",
+			 G_CALLBACK(&gtk_form_child_unmap), child);
+#else
 	gtk_signal_connect(GTK_OBJECT(child->widget), "map",
 			   GTK_SIGNAL_FUNC(&gtk_form_child_map), child);
 	gtk_signal_connect(GTK_OBJECT(child->widget), "unmap",
 			   GTK_SIGNAL_FUNC(&gtk_form_child_unmap), child);
+#endif
     }
+#if GTK_CHECK_VERSION(3,0,0)
+    else if (!gtk_widget_get_realized(child->widget))
+#else
     else if (!GTK_WIDGET_REALIZED(child->widget))
+#endif
     {
 	gtk_widget_set_parent_window(child->widget, form->bin_window);
     }
@@ -627,8 +949,14 @@
     gtk_form_attach_child_window(form, child);
     gtk_widget_realize(child->widget);
 
+#if !GTK_CHECK_VERSION(3,16,0)
     if (child->window == NULL) /* might be already set, see above */
+# if GTK_CHECK_VERSION(3,0,0)
+	gtk_form_set_static_gravity(gtk_widget_get_window(child->widget), TRUE);
+# else
 	gtk_form_set_static_gravity(child->widget->window, TRUE);
+# endif
+#endif
 }
 
     static void
@@ -646,9 +974,18 @@
     {
 	if (!child->mapped)
 	{
+#if GTK_CHECK_VERSION(3,0,0)
+	    if (gtk_widget_get_mapped(GTK_WIDGET(form))
+		    && gtk_widget_get_visible(child->widget))
+#else
 	    if (GTK_WIDGET_MAPPED(form) && GTK_WIDGET_VISIBLE(child->widget))
+#endif
 	    {
+#if GTK_CHECK_VERSION(3,0,0)
+		if (!gtk_widget_get_mapped(child->widget))
+#else
 		if (!GTK_WIDGET_MAPPED(child->widget))
+#endif
 		    gtk_widget_map(child->widget);
 
 		child->mapped = TRUE;
@@ -659,15 +996,31 @@
 	if (force_allocate)
 	{
 	    GtkAllocation allocation;
+#if GTK_CHECK_VERSION(3,0,0)
+	    GtkRequisition requisition;
 
+	    gtk_widget_get_preferred_size(child->widget, &requisition, NULL);
+#endif
+
+#if GTK_CHECK_VERSION(3,0,0)
+	    if (!gtk_widget_get_has_window(child->widget))
+#else
 	    if (GTK_WIDGET_NO_WINDOW(child->widget))
+#endif
 	    {
 		if (child->window)
 		{
+#if GTK_CHECK_VERSION(3,0,0)
+		    gdk_window_move_resize(child->window,
+			    x, y,
+			    requisition.width,
+			    requisition.height);
+#else
 		    gdk_window_move_resize(child->window,
 			    x, y,
 			    child->widget->requisition.width,
 			    child->widget->requisition.height);
+#endif
 		}
 
 		allocation.x = 0;
@@ -679,8 +1032,13 @@
 		allocation.y = y;
 	    }
 
+#if GTK_CHECK_VERSION(3,0,0)
+	    allocation.width = requisition.width;
+	    allocation.height = requisition.height;
+#else
 	    allocation.width = child->widget->requisition.width;
 	    allocation.height = child->widget->requisition.height;
+#endif
 
 	    gtk_widget_size_allocate(child->widget, &allocation);
 	}
@@ -691,7 +1049,11 @@
 	{
 	    child->mapped = FALSE;
 
+#if GTK_CHECK_VERSION(3,0,0)
+	    if (gtk_widget_get_mapped(child->widget))
+#else
 	    if (GTK_WIDGET_MAPPED(child->widget))
+#endif
 		gtk_widget_unmap(child->widget);
 	}
     }
@@ -717,6 +1079,7 @@
  * them or discards them, depending on whether we are obscured
  * or not.
  */
+#if !GTK_CHECK_VERSION(3,0,0)
     static GdkFilterReturn
 gtk_form_filter(GdkXEvent *gdk_xevent, GdkEvent *event UNUSED, gpointer data)
 {
@@ -783,7 +1146,9 @@
     }
     return GDK_FILTER_CONTINUE;
 }
+#endif /* !GTK_CHECK_VERSION(3,0,0) */
 
+#if !GTK_CHECK_VERSION(3,16,0)
     static void
 gtk_form_set_static_gravity(GdkWindow *window, gboolean use_static)
 {
@@ -791,13 +1156,18 @@
      * results in an annoying assertion error message. */
     gdk_window_set_static_gravities(window, use_static);
 }
+#endif /* !GTK_CHECK_VERSION(3,16,0) */
 
     void
 gtk_form_move_resize(GtkForm *form, GtkWidget *widget,
 		     gint x, gint y, gint w, gint h)
 {
+#if GTK_CHECK_VERSION(3,0,0)
+    gtk_widget_set_size_request(widget, w, h);
+#else
     widget->requisition.width  = w;
     widget->requisition.height = h;
+#endif
 
     gtk_form_move(form, widget, x, y);
 }
@@ -811,11 +1181,24 @@
     widget = GTK_WIDGET(form);
 
     event.type = GDK_CONFIGURE;
+#if GTK_CHECK_VERSION(3,0,0)
+    event.window = gtk_widget_get_window(widget);
+    {
+	GtkAllocation allocation;
+
+	gtk_widget_get_allocation(widget, &allocation);
+	event.x = allocation.x;
+	event.y = allocation.y;
+	event.width = allocation.width;
+	event.height = allocation.height;
+    }
+#else
     event.window = widget->window;
     event.x = widget->allocation.x;
     event.y = widget->allocation.y;
     event.width = widget->allocation.width;
     event.height = widget->allocation.height;
+#endif
 
     gtk_main_do_event((GdkEvent*)&event);
 }
@@ -841,4 +1224,3 @@
     child->mapped = FALSE;
     gdk_window_hide(child->window);
 }
-