Make use of native file dialogs configurable (bug #54607). New qt option "use_native_file_dialogs" to control application of QFileDialog::DontUseNativeDialog: * libgui/src/dialog.cc (FileDialog): * libgui/src/files-dock-widget.cc (popdownmenu_search_dir): * libgui/src/find-files-dialog.cc (browse_folders): * libgui/src/m-editor/file-editor-tab.cc (save_file_as): * libgui/src/main-window.cc (handle_save_workspace_request, handle_load_workspace_request, browse_for_directory, request_open_file): * libgui/src/settings-dialog.cc (get_dir): * libgui/src/shortcut-manager.cc (do_import_export): * libgui/src/variable-editor.cc (save): New checkbox "cb_use_native_file_dialogs" associated with qt option "use_native_file_dialogs": * libgui/src/settings-dialog.cc (settings_dialog, write_changed_settings): * libgui/src/settings-dialog.ui:

--- a/libgui/src/m-editor/file-editor-tab.cc	Fri Nov 16 19:52:35 2018 +0100
+++ b/libgui/src/m-editor/file-editor-tab.cc	Sat Nov 17 10:41:07 2018 +0100
@@ -2228,6 +2228,11 @@
     fileDialog->setAcceptMode (QFileDialog::AcceptSave);
     fileDialog->setViewMode (QFileDialog::Detail);
 
+    // FIXME: Remove, if for all common KDE versions (bug #54607) is resolved.
+    if (! resource_manager::get_settings ()->value ("use_native_file_dialogs",
+                                                    true).toBool ())
+      fileDialog->setOption(QFileDialog::DontUseNativeDialog);
+
     connect (fileDialog, SIGNAL (filterSelected (const QString&)),
              this, SLOT (handle_save_as_filter_selected (const QString&)));