Replace Trash action with Delete as needed (Bug #15352)

We keep the grayed out "Move to Trash" action in directories which are
not writable, but otherwise we show the "Delete" action for files that
cannot be trashed.

Regardless of the "Move to Trash" action's visibility, it should remain
sensitive for keyboard shortcuts to work (i.e.: pressing the Delete key).

Follow-up fix for https://bugzilla.xfce.org/show_bug.cgi?id=15352.

thunar/thunar-standard-view.c

@@ -4472,6 +4472,7 @@ thunar_standard_view_selection_changed (ThunarStandardView *standard_view)
   gboolean    pastable;
   gboolean    writable;
   gboolean    trashed;
+  gboolean    hide_trash_action;
   gboolean    show_delete_action;
   GList      *lp, *selected_files;
   gint        n_selected_files = 0;
@@ -4516,11 +4517,16 @@ thunar_standard_view_selection_changed (ThunarStandardView *standard_view)
   /* and setup the new selected files list */
   standard_view->priv->selected_files = selected_files;
 
-  /* check whether the folder displayed by the view is writable/in the trash/can be trashed */
+  /* check whether the folder displayed by the view is writable/in the trash */
   current_directory = thunar_navigator_get_current_directory (THUNAR_NAVIGATOR (standard_view));
   writable = (current_directory != NULL && thunar_file_is_writable (current_directory));
   trashed = (current_directory != NULL && thunar_file_is_trashed (current_directory));
 
+  /* if moving to trash is not applicable, replace it with the delete action */
+  hide_trash_action = trashed || !trashable || !thunar_g_vfs_is_uri_scheme_supported ("trash");
+  /* but only if the directory is writable -- keep "move to trash" otherwise */
+  hide_trash_action &= writable;
+
   g_object_get (G_OBJECT (standard_view->preferences), "misc-show-delete-action", &show_delete_action, NULL);
 
   /* check whether the clipboard contains data that can be pasted here */
@@ -4565,8 +4571,8 @@ G_GNUC_END_IGNORE_DEPRECATIONS
 
   /* update the "Move to Trash" action */
   g_object_set (G_OBJECT (standard_view->priv->action_move_to_trash),
-                "sensitive", (n_selected_files > 0) && trashable,
-                "visible", !trashed && thunar_g_vfs_is_uri_scheme_supported ("trash"),
+                "sensitive", (n_selected_files > 0) && writable,
+                "visible", !hide_trash_action,
                 "tooltip", ngettext ("Move the selected file to the Trash",
                                      "Move the selected files to the Trash",
                                      n_selected_files),
@@ -4575,7 +4581,7 @@ G_GNUC_END_IGNORE_DEPRECATIONS
   /* update the "Delete" action */
   g_object_set (G_OBJECT (standard_view->priv->action_delete),
                 "sensitive", (n_selected_files > 0) && writable,
-                "visible", trashed || !thunar_g_vfs_is_uri_scheme_supported ("trash") || show_delete_action,
+                "visible", hide_trash_action || show_delete_action,
                 "tooltip", ngettext ("Permanently delete the selected file",
                                      "Permanently delete the selected files",
                                      n_selected_files),