When offering a ward to a subject of a ruler sometimes you can't close the window. For example, playing Vratislav II of Bohemia and offering Judita to Princess Adela of the Holy Roman Empire, the window is too large and the "send offer" button is cut off at the bottom. Tried "tabbing" and sometimes worked but it's problematic. Offering a ward directly to a ruler works fine as long as the window doesn't get too large. I noticed this after the last patch.