Paintbrushing Eraser!

[halligant]

Hello,
          I've recently downloaded gimp 2.10 and I find that when I utilise the eraser
function it behaves like the paintbrush and paints the photograph with the 
background colour.I should be obliged if anyone could tell me how to remedy this,
                                                                                       Yours,
                                                                                             halligant