When using the Structured Keywords panel randomly the column headings from previous searches don't disappear when going to a different catagory, in my screenshot I was previously in the sport and recreation category then switched to a different category, the columns to the right cleared but the column headings stuck around, this randomly seems to happen. I can get the column headings to clear if I slightly resize the dialog box on the right side to make it slightly smaller.
I also noticed that if I close the structured keyword panel, then reopen it, the column heading in the first column to the right will be still be there from the previous search, but under the heading the column will be empty, this seems to be fairly repeatable.