Some additions to the migration guide

docs/reference/gtk/migrating-3to4.xml

@@ -52,6 +52,14 @@
       </para>
     </section>
 
+    <section>
+      <title>Do not use widget style properties</title>
+      <para>
+        Style properties do not exist in GTK+ 4. You should stop using them in
+        your custom CSS.
+      </para>
+    </section>
+
     <section>
       <title>Review your window creation flags</title>
       <para>
@@ -98,6 +106,14 @@
       </para>
     </section>
 
+    <section>
+      <title>Stop using gdk_pixbuf_get_from_window() and gdk_cairo_set_source_window()</title>
+      <para>
+        These functions are not supported in GTK+ 4. Instead, either use backend-specific
+        APIs, or render your widgets using gtk_widget_render().
+      </para>
+    </section>
+
   </section>
 
   <section>
@@ -110,6 +126,17 @@
       have been either impossible or impractical.
     </para>
 
+    <section>
+      <title>Adapt to GdkWindow API changes</title>
+      <para>
+        The gdk_window_new() function has been replaced by a number of more
+        specialized constructors: gdk_window_new_toplevel(), gdk_window_new_popup(),
+        gdk_window_new_temp(), gdk_window_new_child(), gdk_window_new_input(),
+        gdk_wayland_window_new_subsurface(). Use the appropriate ones to create
+        your windows.
+      </para>
+    </section>
+
     <section>
       <title>Adapt to GtkStyleContext API changes</title>
       <para>
@@ -121,6 +148,15 @@
       </para>
     </section>
 
+    <section>
+      <title>Adapt to GtkCssProvider API changes</title>
+      <para>
+        In GTK+ 4, the various #GtkCssProvider load functions have lost
+        their #GError argument. If you want to handle CSS loading errors,
+        use the #GtkCssProvider::parsing-error signal instead.
+      </para>
+    </section>
+
     <section>
       <title>Stop using GtkContainer::border-width</title>
       <para>
@@ -149,6 +185,14 @@
       </para>
     </section>
 
+    <section>
+      <title>Use gtk_widget_measure</title>
+      <para>
+        gtk_widget_measure replaces the various gtk_widget_get_preferred_ functions
+        for querying sizes.
+      </para>
+    </section>
+
     <section>
       <title>Adapt to drawing model changes</title>
       <para>