Why some text are "invisible" sometimes ? [Xara Pro 10]

[MVMusic]

Yes, I was a little stumped and about to give up when I remember the stroke issue...

[stephane_fr]

I think you found the issue

Indeed there must be different species in these texts. But I need to understand what do you call a "strike" here ? (and outline ? a shadow ? nope...)

Edit : oh, I didn't see there was 2 pages.. I'm going to read this.. Thank you