if a tool doesn't work, what can be the problem?

[cimerio]

I opened a jpg image, but want erase a part.

I went to Pixel Persona, Erase Brush Tool. and the "circle" of tool shows.

But doesn't erase nothing. 

 

The status says: Drag to start erasing. But doesn't work.

[walt.farrell]

3 minutes ago, cimerio said:

The status says: Drag to start erasing. But doesn't work.

Do you know that "Drag" means "click and hold the left-mouse button and move the mouse"?

[Alfred]

In the Layers panel, is the JPEG layer identified as a ‘Pixel’ layer rather than an ‘Image’ layer?

What brush are you using with the Erase Brush Tool? Check that the Hardness, Flow and Opacity are all at or near 100%.

[cimerio]

yes, for two questions.

I don't know what happened. It's working now.

the cursor didn't erased nothing. maybe, it was a protected file, a raster image... unfortunately, I can't tell now.