Thanks for pointing this out Loci. I'll see to it that it gets fixed.

Still an issue in 20180525-f7af35c587-win_x86-devprev.

The popup says:

Select the segments you want to mutate. Click the Mutate Button from the menu. Then click the picture of the sidechain you want to mutate to.

You can't really select segments in an intro puzzle. Something like:

Click on a segment you want to mutate, then pick the sidechain you want from the pie menu.

would be clearer.

Thanks, should be addressed next patch.

Thanks, should be addressed next patch.

Resolved in 20180725-d14dae34c3-win_x86-devprev.

Closing.