settings: Switch to XfceTitledDialog

This also means we introduce libxfce4ui as a dependency.

configure.ac.in

@@ -69,6 +69,7 @@ XDT_CHECK_LIBX11_REQUIRE()
 XDT_CHECK_PACKAGE([LIBXMU], [xmu], [1.1.2])
 XDT_CHECK_PACKAGE([GTK3], [gtk+-3.0], [3.22.0])
 XDT_CHECK_PACKAGE([CAIRO], [cairo], [1.5.0])
+XDT_CHECK_PACKAGE([LIBXFCE4UI], [libxfce4ui-2], [4.14.0])
 
 dnl ***********************************
 dnl *** Check for optional packages ***

src/Makefile.am

@@ -12,6 +12,7 @@ xfce4_taskmanager_CFLAGS =						\
 	$(LIBXMU_CFLAGS)						\
 	$(GTK3_CFLAGS)							\
 	$(WNCK_CFLAGS)							\
+	$(LIBXFCE4UI_CFLAGS)				\
 	$(NULL)
 
 xfce4_taskmanager_LDADD = 						\
@@ -20,6 +21,7 @@ xfce4_taskmanager_LDADD = 						\
 	$(LIBXMU_LIBS)						\
 	$(GTK3_LIBS) 						\
 	$(WNCK_LIBS)						\
+	$(LIBXFCE4UI_LIBS)			\
 	$(NULL)
 
 xfce4_taskmanager_SOURCES =						\

src/settings-dialog.ui

@@ -17,14 +17,11 @@
     <property name="can_focus">False</property>
     <property name="icon_name">window-close-symbolic</property>
   </object>
-  <object class="GtkDialog" id="settings-dialog">
+  <object class="XfceTitledDialog" id="settings-dialog">
     <property name="can_focus">False</property>
     <property name="title" translatable="yes">Task Manager Settings</property>
     <property name="icon_name">org.xfce.taskmanager</property>
     <property name="type_hint">dialog</property>
-    <child type="titlebar">
-      <placeholder/>
-    </child>
     <child internal-child="vbox">
       <object class="GtkBox">
         <property name="can_focus">False</property>