Do not switch to default content after frame screenshot. Leave it to the user

Author: glibas

src/main/java/com/assertthat/selenium_shutterbug/core/Snapshot.java

@@ -224,7 +224,6 @@ public void save() {
         if (title != null && !title.isEmpty()) {
             image = ImageProcessor.addTitle(image, title, Color.red, new Font("Serif", Font.BOLD, 20));
         }
-        driver.switchTo().defaultContent();
         FileUtil.writeImage(image, EXTENSION, screenshotFile);
     }