Resolves: tdf#108419 use spinfield preferred size as transparency widget size

Change-Id: I7b5c8aeb087efe007c687dc1f206bcb0e8b0173e
Reviewed-on: https://gerrit.libreoffice.org/38864
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/svx/source/tbxctrls/grafctrl.cxx b/svx/source/tbxctrls/grafctrl.cxx
index 2a20d01..4c58847 100644
--- a/svx/source/tbxctrls/grafctrl.cxx
+++ b/svx/source/tbxctrls/grafctrl.cxx
@@ -92,11 +92,8 @@ ImplGrafMetricField::ImplGrafMetricField( vcl::Window* pParent, const OUString& 
    maCommand( rCmd ),
    mxFrame( rFrame )
{
    Size aSize( GetTextWidth( "-100 %" ), GetTextHeight() );

    aSize.Width() += 20;
    aSize.Height() += 6;
    SetSizePixel( aSize );
    Size aSize(CalcMinimumSizeForText("-100 %"));
    SetSizePixel(aSize);

    if ( maCommand == ".uno:GrafGamma" )
    {