diff --git a/scribus/scribus.cpp b/scribus/scribus.cpp
index 966362a..a6a66b6 100644
--- a/scribus/scribus.cpp
+++ b/scribus/scribus.cpp
@@ -6539,6 +6539,7 @@ void ScribusMainWindow::slotPrefsOrg()
 	slotSelect();
 	struct ApplicationPrefs oldPrefs(prefsManager->appPrefs);
 	PreferencesDialog prefsDialog(this, oldPrefs);
+  prefsDialog.setWindowModality( Qt::WindowModal );
 	int prefsResult=prefsDialog.exec();
 	if (prefsResult==QDialog::Accepted)
 	{

diff --git a/scribus/scribus.cpp b/scribus/scribus.cpp
index 966362a..b30cba9 100644
--- a/scribus/scribus.cpp
+++ b/scribus/scribus.cpp
@@ -7679,12 +7679,13 @@ void ScribusMainWindow::GroupObj(bool showLockDia)
 		}
 		if (lockedCount!=0 && lockedCount!=selectedItemCount)
 		{
-			ScMessageBox msgBox;
+			ScMessageBox msgBox(this);
 			QPushButton *abortButton = msgBox.addButton(QMessageBox::Cancel);
 			QPushButton *lockButton = msgBox.addButton(tr("&Lock All"), QMessageBox::AcceptRole);
 			msgBox.addButton(tr("&Unlock All"), QMessageBox::AcceptRole);
 			msgBox.setIcon(QMessageBox::Warning);
 			msgBox.setWindowTitle(CommonStrings::trWarning);
+      msgBox.setWindowModality( Qt::WindowModal );
 			msgBox.setText( tr("Some objects are locked."));
 			msgBox.setDefaultBatchButton(lockButton);
 			msgBox.exec();