Skip paint event when in the middle of a buffer operation

[lyx.git] / src / frontends / qt4 / GuiWorkArea.cpp

diff --git a/src/frontends/qt4/GuiWorkArea.cpp b/src/frontends/qt4/GuiWorkArea.cpp
index d68185c4b6af4753961caf5bcc33048703ab9f98..5835cbd9b63e061f4fa38025978fab506c460d41 100644 (file)
--- a/src/frontends/qt4/GuiWorkArea.cpp
+++ b/src/frontends/qt4/GuiWorkArea.cpp
@@ -1245,10 +1245,12 @@ void GuiWorkArea::Private::paintPreeditText(GuiPainter & pain)
 void GuiWorkArea::paintEvent(QPaintEvent * ev)
 {
        // Do not trigger the painting machinery if we are not ready (see
-       // bug #10989). However, since macOS has turned the screen black at
-       // this point, our backing store has to be copied to screen.
-       if (view().busy()) {
-               // this is a no-op except on macOS.
+       // bug #10989). The second test triggers when in the middle of a
+       // dispatch operation.
+       if (view().busy() || d->buffer_view_->buffer().undo().activeUndoGroup()) {
+               // Since macOS has turned the screen black at this point, our
+               // backing store has to be copied to screen (this is a no-op
+               // except on macOS).
                d->updateScreen(ev->rect());
                ev->accept();
                return;