[LyX/master] #12001 make message boxes modal on Mac

[Stephan Witt]

commit 550c79215b16d89a7f849145520741ba3400f58b
Author: Stephan Witt <switt at lyx.org>
Date:   Wed Aug 2 17:59:46 2023 +0200

    #12001 make message boxes modal on Mac
---
 src/frontends/qt/GuiAlert.cpp |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/src/frontends/qt/GuiAlert.cpp b/src/frontends/qt/GuiAlert.cpp
index 288289c..30f55eb 100644
--- a/src/frontends/qt/GuiAlert.cpp
+++ b/src/frontends/qt/GuiAlert.cpp
@@ -113,6 +113,9 @@ buttonid doPrompt(docstring const & title, docstring const & question,
 	QMessageBox msg_box(QMessageBox::Information,
 			toqstr(title), toqstr(question),
 			QMessageBox::NoButton, qApp->focusWidget());
+#ifdef Q_OS_MAC
+	msg_box.setWindowModality(Qt::WindowModal);
+#endif
 	b[0] = msg_box.addButton(b1.empty() ? "OK" : toqstr(b1),
 					QMessageBox::ActionRole);
 	if (!b2.empty())