tdf#108932 - prevent textbox shrink from actually growing

fix regression from a4dee94a for
a particular situation - where the textbox flowed onto the following
page.

Change-Id: I58fe2909411c4e5e484083cfc395976f0bc4ba17
Reviewed-on: https://gerrit.libreoffice.org/40558Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Justin Luth <justin_luth@sil.org>

sw/source/core/objectpositioning/anchoredobjectposition.cxx

@@ -489,7 +489,9 @@ SwTwips SwAnchoredObjectPosition::ImplAdjustVertRelPos( const SwTwips nTopOfAnch
         // tdf#101627 - the patch a4dee94afed9ade6ac50237c8d99a6e49d3bebc1
         //              for tdf#91260 causes problems if the textbox
         //              is anchored in the footer, so exclude this case
+        // tdf#108932 - ensure that the adjustment will only shrink (> 0)
         if ( !( GetAnchorFrame().GetUpper() && GetAnchorFrame().GetUpper()->IsFooterFrame() )
+             && nAdjustedRelPosY > 0
              && nAdjustedRelPosY < nProposedRelPosY )
         {
             const SwFrameFormat* pFormat = &(GetFrameFormat());