Don't try to show the status message if we are busy.

Intended to fix #8523.
(cherry picked from commit 6dac777dbc)

src/frontends/qt4/GuiView.cpp

@@ -1061,6 +1061,8 @@ void GuiView::updateStatusBar()
 
 void GuiView::showMessage()
 {
+	if (busy_)
+		return;
 	QString msg = toqstr(theGuiApp()->viewStatusMessage());
 	if (msg.isEmpty()) {
 		BufferView const * bv = currentBufferView();

status.20x

@@ -55,6 +55,7 @@ What's new
 
 * USER INTERFACE
 
+- Fix crash when saving document with module that is not present (bug 8523).
 
 
 * DOCUMENTATION AND LOCALIZATION