strokeStyle changes PRIOR lines

I’m making a graph in Canvas. I plot the grid with ctx.strokeStyle = ‘#ccc’;

I then plot the data lines with ctx.strokeStyle = ‘#000’;, and the GRID then turns to ‘#000’ too! The same happens with any color.

The same happens with lineWidth.

The fillStyle of the labels is not affected.

It happens even if I surround the code with save/restore.

It happens in both Firefox and Chrome.

Has anyone else had this problem? Is there any way around it?