It turns out that my initial click in the window corner instinctively happens in an area where the window doesn’t respond to ...

You can round corners in Illustrator by first converting an anchor point -- a handle that you use to shape curves -- from a straight anchor to a curved one. Then you smooth the corners manually and ...

Photographs and any other pictures can be given smooth round edges to make them look nicer. Maybe you want to use the photographs in a collage for print or digital or put them on your website, blog ...