[LyX/master] Amend 9e645a5cfc9d6c3e66d

[Juergen Spitzmueller]

commit a8947aaad876bfdf8c5b2234ef300ef790112b61
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Mon Aug 8 09:49:51 2022 +0200

    Amend 9e645a5cfc9d6c3e66d
    
    Only show "System Default" if auto-open is available for the current
    format.
---
 src/frontends/qt/GuiPrefs.cpp |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/frontends/qt/GuiPrefs.cpp b/src/frontends/qt/GuiPrefs.cpp
index e607471..5fa3b94 100644
--- a/src/frontends/qt/GuiPrefs.cpp
+++ b/src/frontends/qt/GuiPrefs.cpp
@@ -2325,7 +2325,8 @@ void PrefFileformats::updateViewers()
 	viewerCO->blockSignals(true);
 	viewerCO->clear();
 	viewerCO->addItem(qt_("None"), QString());
-	viewerCO->addItem(qt_("System Default"), QString("auto"));
+	if (os::canAutoOpenFile(f.extension(), os::VIEW))
+		viewerCO->addItem(qt_("System Default"), QString("auto"));
 	updateComboBox(viewer_alternatives, f.name(), viewerCO);
 	viewerCO->addItem(qt_("Custom"), QString("custom viewer"));
 	viewerCO->blockSignals(false);
@@ -2349,7 +2350,8 @@ void PrefFileformats::updateEditors()
 	editorCO->blockSignals(true);
 	editorCO->clear();
 	editorCO->addItem(qt_("None"), QString());
-	editorCO->addItem(qt_("System Default"), QString("auto"));
+	if (os::canAutoOpenFile(f.extension(), os::EDIT))
+		editorCO->addItem(qt_("System Default"), QString("auto"));
 	updateComboBox(editor_alternatives, f.name(), editorCO);
 	editorCO->addItem(qt_("Custom"), QString("custom editor"));
 	editorCO->blockSignals(false);