You may find yourself in this strange situation, when the graph of your audio channels in Audacity has a lighter background that covers your selections, being in between your selections and the waveform, this way making it difficult to define accurately the part you need to copy or delete.

You don’t need to upgrade Audacity or change anything in the preferences. Just make sure you have not pressed by accident (or forgotten from a previous session) the “multi-tool mode” button, the one that resembles an asterisk.

Press the button of the “Selection Tool” (a vertical line at the upper left corner of the “Tools” toolbar), and the background in the wave graphs will disappear. Once again you are free to select and cut as always.