Insert only single empty text
Insert only single empty text

Change-Id: Ic2ef7a1f9694de48a2295cec7269410020f8cb06

sdteffen/libvisio,LibreOffice/libvisio,sdteffen/libvisio,LibreOffice/libvisio,LibreOffice/libvisio,sdteffen/libvisio,sdteffen/libvisio