Resolves: tdf#151509 don't overwrite geometry for system childs

Change-Id: I5ad73d0bd138b2ba1b99d63bca97773f43e39606
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/142274
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/vcl/unx/gtk3/gtkframe.cxx b/vcl/unx/gtk3/gtkframe.cxx
index d4084ca..b73304a 100644
--- a/vcl/unx/gtk3/gtkframe.cxx
+++ b/vcl/unx/gtk3/gtkframe.cxx
@@ -3133,6 +3133,10 @@ bool GtkSalFrame::DrawingAreaButton(SalEvent nEventType, int nEventX, int nEvent

void GtkSalFrame::UpdateGeometryFromEvent(int x_root, int y_root, int nEventX, int nEventY)
{
    //tdf#151509 don't overwrite geometry for system childs
    if (m_nStyle & SalFrameStyleFlags::SYSTEMCHILD)
        return;

    int frame_x = x_root - nEventX;
    int frame_y = y_root - nEventY;
    if (m_bGeometryIsProvisional || frame_x != maGeometry.x() || frame_y != maGeometry.y())