Using various browsers (and devices) Open page with Atto editor. Type several words. Select text and click bold button Verify the button is highlighted. Click in middle of text. Click bold button and verify that highlighting of button changes immediately. (with IE nothing should happen) Type text and verify that it has correct format and that highlight remains correct. (with IE nothing should happen) Repeat with other formating keys ie italic, underline, sub, sup. Check the other buttons to see that the highlight does not change unexpectedly. Try clicking a button of an empty browser, and type several characters. Verify that the highlighting toggles initially and remains constant. Click two or more buttons in succession. Only the last button pressed should appear different than the starting value. Type a character and verify that character has the formating that was shown before key press and that the highlight matches again afterwards. Repeat the previous tests using hot key ctrl-b, ctrl-i etc. or a mixture of hot keys and clicking buttons.