diff -ura package.orig/Thunar-1.8.2/thunar/thunar-progress-dialog.c package.new/Thunar-1.8.2/thunar/thunar-progress-dialog.c
--- package.orig/Thunar-1.8.2/thunar/thunar-progress-dialog.c	2019-01-01 20:59:23.209820558 +0530
+++ package.new/Thunar-1.8.2/thunar/thunar-progress-dialog.c	2019-01-01 20:53:25.446491100 +0530
@@ -368,6 +368,7 @@
       dialog->scrollwin = gtk_scrolled_window_new (NULL, NULL);
       gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (dialog->scrollwin),
                                       GTK_POLICY_NEVER, GTK_POLICY_AUTOMATIC);
+      gtk_widget_set_vexpand (dialog->scrollwin, TRUE);
       gtk_container_add (GTK_CONTAINER (dialog->vbox), dialog->scrollwin);
       gtk_widget_show (dialog->scrollwin);
 
Only in package.orig: scroll_patch.patch