Possible bug with simultaneous work "gtk-rs" and "xlsxwriter-rs" crates

[dgr113]

If I run a function that writes in Excel BEFORE running the GTK GUI the numeric data is written correctly.
But if I start writing AFTER GUI... then f64 numbers are written as integers =(

"LC_ALL=C" compilation env set helped me, but crate docs doesn't contain this.
This was suggested to me by "gtk-rs" maintainers. Thanks to them =)

My GIT example