cannot round corners on a live shape??
I drew a shape using the rectangle tool-drawing multiple rectangles and placing them on top of each other- then used the pathfinder > unite option to combine the shapes into one single shape.
Then, I went in to round the corners by selecting portions of the shape with the direct selection tool. It worked for most of the shape but on the last section I absolutely cannot get rounded corners.
Here is a screenshot of the shape. You will see I have successfully rounded most of the other corners but that last section will not even show the live corner widget when I select the anchor points with the direct selection tool. Please tell me why this is happening and how to fix it.

