diff -Nru gtk+3.0-3.22.30/debian/changelog gtk+3.0-3.22.30/debian/changelog
--- gtk+3.0-3.22.30/debian/changelog	2019-04-02 15:46:36.000000000 +0000
+++ gtk+3.0-3.22.30/debian/changelog	2019-07-11 08:29:12.000000000 +0000
@@ -1,3 +1,12 @@
+gtk+3.0 (3.22.30-1ubuntu4) bionic; urgency=medium
+
+  * debian/patches/print-dialog-check-cups-custom-options.patch:
+    - Print dialog: Check whether an unknown option setting is actually a
+      custom setting, patch from upstream (LP: #1763520, Upstream merge
+      request: #434, #717).
+
+ -- Till Kamppeter <till.kamppeter@gmail.com>  Wed,  5 Jun 2019 15:46:01 +0200
+
 gtk+3.0 (3.22.30-1ubuntu3) bionic; urgency=medium
 
   [ Sebastien Bacher ]
diff -Nru gtk+3.0-3.22.30/debian/patches/print-dialog-cups-check-unknown-option-values-whether-they-are-actually-custom-settings.patch gtk+3.0-3.22.30/debian/patches/print-dialog-cups-check-unknown-option-values-whether-they-are-actually-custom-settings.patch
--- gtk+3.0-3.22.30/debian/patches/print-dialog-cups-check-unknown-option-values-whether-they-are-actually-custom-settings.patch	1970-01-01 00:00:00.000000000 +0000
+++ gtk+3.0-3.22.30/debian/patches/print-dialog-cups-check-unknown-option-values-whether-they-are-actually-custom-settings.patch	2019-07-11 08:29:12.000000000 +0000
@@ -0,0 +1,129 @@
+--- a/modules/printbackends/cups/gtkprintbackendcups.c
++++ b/modules/printbackends/cups/gtkprintbackendcups.c
+@@ -595,9 +595,14 @@
+ 
+ typedef struct {
+   GtkCupsRequest *request;
++  GtkPageSetup *page_setup;
+   GtkPrinterCups *printer;
+ } CupsOptionsData;
+ 
++#define UNSIGNED_FLOAT_REGEX "([0-9]+([.,][0-9]*)?|[.,][0-9]+)([e][+-]?[0-9]+)?"
++#define SIGNED_FLOAT_REGEX "[+-]?"UNSIGNED_FLOAT_REGEX
++#define SIGNED_INTEGER_REGEX "[+-]?([0-9]+)"
++
+ static void
+ add_cups_options (const gchar *key,
+ 		  const gchar *value,
+@@ -621,7 +626,7 @@
+ 
+   key = key + strlen ("cups-");
+ 
+-  if (printer && printer->ppd_file)
++  if (printer && printer->ppd_file && !g_str_has_prefix (value, "Custom."))
+     {
+       ppd_coption_t *coption;
+       gboolean       found = FALSE;
+@@ -642,14 +647,74 @@
+             }
+ 
+           if (custom_values_enabled && !found)
+-            custom_value = TRUE;
++            {
++              /* Check syntax of the invalid choice to see whether
++                 it could be a custom value */
++              if (g_str_equal (key, "PageSize") ||
++                  g_str_equal (key, "PageRegion"))
++                {
++                  /* Handle custom page sizes... */
++                  if (g_regex_match_simple ("^" UNSIGNED_FLOAT_REGEX "x" UNSIGNED_FLOAT_REGEX "(cm|mm|m|in|ft|pt)?$", value, G_REGEX_CASELESS, 0))
++                    custom_value = TRUE;
++                  else
++                    {
++                      if (data->page_setup != NULL)
++                        {
++                          custom_value = TRUE;
++                          new_value =
++                            g_strdup_printf ("Custom.%.2fx%.2fmm",
++                                             gtk_paper_size_get_width (gtk_page_setup_get_paper_size (data->page_setup), GTK_UNIT_MM),
++                                             gtk_paper_size_get_height (gtk_page_setup_get_paper_size (data->page_setup), GTK_UNIT_MM));
++                        }
++                    }
++                }
++              else
++                {
++                  /* Handle other custom options... */
++                  ppd_cparam_t  *cparam;
++
++                  cparam = (ppd_cparam_t *) cupsArrayFirst (coption->params);
++                  if (cparam != NULL)
++                    {
++                      switch (cparam->type)
++                        {
++                        case PPD_CUSTOM_CURVE :
++                        case PPD_CUSTOM_INVCURVE :
++                        case PPD_CUSTOM_REAL :
++                          if (g_regex_match_simple ("^" SIGNED_FLOAT_REGEX "$", value, G_REGEX_CASELESS, 0))
++                            custom_value = TRUE;
++                          break;
++
++                        case PPD_CUSTOM_POINTS :
++                          if (g_regex_match_simple ("^" SIGNED_FLOAT_REGEX "(cm|mm|m|in|ft|pt)?$", value, G_REGEX_CASELESS, 0))
++                            custom_value = TRUE;
++                          break;
++
++                        case PPD_CUSTOM_INT :
++                          if (g_regex_match_simple ("^" SIGNED_INTEGER_REGEX "$", value, G_REGEX_CASELESS, 0))
++                            custom_value = TRUE;
++                          break;
++
++                        case PPD_CUSTOM_PASSCODE :
++                        case PPD_CUSTOM_PASSWORD :
++                        case PPD_CUSTOM_STRING :
++                          custom_value = TRUE;
++                          break;
++
++                        default :
++                          custom_value = FALSE;
++                        }
++                    }
++                }
++            }
+         }
+     }
+ 
+   /* Add "Custom." prefix to custom values if not already added. */
+-  if (custom_value && !g_str_has_prefix (value, "Custom."))
++  if (custom_value)
+     {
+-      new_value = g_strdup_printf ("Custom.%s", value);
++      if (new_value == NULL)
++        new_value = g_strdup_printf ("Custom.%s", value);
+       gtk_cups_request_encode_option (request, key, new_value);
+       g_free (new_value);
+     }
+@@ -668,6 +733,7 @@
+   GtkPrinterCups *cups_printer;
+   CupsPrintStreamData *ps;
+   CupsOptionsData *options_data;
++  GtkPageSetup *page_setup;
+   GtkCupsRequest *request = NULL;
+   GtkPrintSettings *settings;
+   const gchar *title;
+@@ -773,10 +839,16 @@
+     g_free (title_truncated);
+   }
+ 
++  g_object_get (job,
++                "page-setup", &page_setup,
++                NULL);
++
+   options_data = g_new0 (CupsOptionsData, 1);
+   options_data->request = request;
+   options_data->printer = cups_printer;
++  options_data->page_setup = page_setup;
+   gtk_print_settings_foreach (settings, add_cups_options, options_data);
++  g_clear_object (&page_setup);
+   g_free (options_data);
+ 
+   ps = g_new0 (CupsPrintStreamData, 1);
diff -Nru gtk+3.0-3.22.30/debian/patches/series gtk+3.0-3.22.30/debian/patches/series
--- gtk+3.0-3.22.30/debian/patches/series	2019-04-02 15:46:36.000000000 +0000
+++ gtk+3.0-3.22.30/debian/patches/series	2019-07-11 08:29:12.000000000 +0000
@@ -25,3 +25,4 @@
 unity-headerbar-maximized-mode.patch
 gtksocket-unscale-before-sending-configurenotify.patch
 Check-for-NULL-priv-popup_window-in-gtk_combo_box_popdown.patch
+print-dialog-cups-check-unknown-option-values-whether-they-are-actually-custom-settings.patch