Have I messed up the audio file, or just the display?

Running Audacity 2.6.2 on Windows 10 Pro

I suspect that I’ve inadvertently used a keyboard shortcut, but as I don’t know which one I don’t know whether I’ve done permanent damage to the file. The display now looks like this:
Why are the bands narrow, all of a sudden.jpg
Previously the background to the Audio Tracks was a uniform dark grey, without this pale grey band from -0.5 to 0.5, and without the white scale at the beginning.

Please can someone tell me (a) whether it will affect the audio file, and (b) how I get back to the display I’m used to? I apologise for posting this, as I imagine the answer is somewhere in the FAQs, but as I don’t know what this effect is called I don’t know where to look!

Many thanks, Bill

You selected the Envelope Tool (two arrows and bent line). Normal display is with the “I-Beam” tool.

While you’re there, the Envelope Tool will allow you to make second-by-second changes in sound volume just by drawing them in. Click and pull.

Screen Shot 2020-05-14 at 8.44.55.png

Thanks for solving that one, Koz - It looks as if I must have hit F6 at some point.

I’ve also encountered the white dots which appear in your example, and though I managed to make them go away I now realise their importance.

For now, I’ve clicked back on the I-beam and all is well!

Regards, Bill