gtk: listbox border was not rendered
gtk: listbox border was not rendered

remove extending of pixmapRect in the nPart == PART_WINDOW branch
and simplify code, since rControlRectangle, pixmapRect and widgetRect
are the same.

Change-Id: I253851fad558e525cd533bb3576a9bba82187e53

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core