port to gtk4

src/screencastdialog.ui

@@ -6,6 +6,7 @@
     <property name="resizable">0</property>
     <property name="default-width">500</property>
     <property name="default-height">300</property>
+    <property name="focus-widget">accept_button</property>
     <child type="titlebar">
       <object class="GtkHeaderBar" id="titlebar">
         <property name="show-title-buttons">false</property>
@@ -14,7 +15,17 @@
             <property name="label" translatable="yes">_Cancel</property>
             <property name="use_underline">1</property>
             <signal name="clicked" handler="button_clicked"/>
-            <accelerator key="Escape" signal="activate"/>
+            <child>
+              <object class="GtkShortcutController">
+                <property name="scope">managed</property>
+                <child>
+                  <object class="GtkShortcut">
+                    <property name="trigger">Escape</property>
+                    <property name="action">activate</property>
+                  </object>
+                </child>
+              </object>
+            </child>
           </object>
         </child>
         <child type="end">
@@ -22,7 +33,6 @@
             <property name="sensitive">0</property>
             <property name="label" translatable="yes">_Share</property>
             <property name="use_underline">1</property>
-            <property name="has-focus">True</property>
             <signal name="clicked" handler="button_clicked"/>
             <style>
               <class name="suggested-action"/>