That happens occasionally, most often when the screen size is smaller than average. Two things to try: 1) Reload the whole page and try again. This often redraws the box correctly 2) Press the horizontal rule button (last button) to insert a horizontal rule. This can force the text box to properly skip down a line and draw. For future reference, what is the device you are using? A tablet, or Chromebook or other device with a slightly smaller screen area?
