Resolves: tdf#119790 for gtk3 save and restore typed name on changing filter

Change-Id: I17c3d154144b13ce401b0e4afe84c91a2fe98d8e
Reviewed-on: https://gerrit.libreoffice.org/63075
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

vcl/unx/gtk/fpicker/SalGtkFilePicker.cxx

@@ -806,7 +806,16 @@ uno::Sequence<OUString> SAL_CALL SalGtkFilePicker::getSelectedFiles()
                             }
                         }
                         if( bChangeFilter && bExtensionTypedIn )
+                        {
+#if GTK_CHECK_VERSION(3,0,0)
+                            gchar* pCurrentName = gtk_file_chooser_get_current_name(GTK_FILE_CHOOSER(m_pDialog));
+                            setCurrentFilter( aNewFilter );
+                            gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(m_pDialog), pCurrentName);
+                            g_free(pCurrentName);
+#else
                             setCurrentFilter( aNewFilter );
+#endif
+                        }
                     }
                 }