Resolves: tdf#152421 'GTK_IS_LABEL (label)' assertion failure

Change-Id: I33d76f4a84d7ef1cd14cb5f2597f38385eff2e2a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/143725
Tested-by: Jenkins
Reviewed-by: Eike Rathke <erack@redhat.com>
diff --git a/sc/uiconfig/scalc/ui/tpviewpage.ui b/sc/uiconfig/scalc/ui/tpviewpage.ui
index 18acb5e..6bbbe4a 100644
--- a/sc/uiconfig/scalc/ui/tpviewpage.ui
+++ b/sc/uiconfig/scalc/ui/tpviewpage.ui
@@ -460,6 +460,7 @@
                    <property name="receives-default">False</property>
                    <property name="xalign">0</property>
                    <property name="draw-indicator">True</property>
                    <property name="label" translatable="no"></property>
                    <child>
                      <placeholder/>
                    </child>