Slide text becomes invisible when using notes and XeLaTex

[Loris Sauter]

Uncommenting the lines after %notes

and using XeLaTex, some text on the slides goes missing / invisble / white.

Apparently, this is a known issue and can be solved by adding

\makeatletter 
\def\beamer@framenotesbegin{% at beginning of slide
     \usebeamercolor[fg]{normal text}
      \gdef\beamer@noteitems{}% 
      \gdef\beamer@notes{}% 
}
\makeatother

to the preamble source

This issue is mainly for self-reference, I will make a PR soon(tm)