SORT: Why is it different in open/save window then elsewhere?

Question

The sort order in my Xubuntu file manager (Thunar) is the way I want it, with types of characters in the following order:

• non alphanumeric (principally: underscore, hyphen, dot)
• numerics
• alphabetics (lowercase, uppercase, and accented characters treated as equal)

When I OPEN an existing file or "SAVE AS" a file in any program, the file/directory listing window puts all of the uppercase characters together, before the lowercase ones. Now with the research I have done I know that the unwanted (by me) lower/uppercase treatment is due to LC_COLLATE=C. I chose 'C' because of the separation it gives between alphanumerics and the other characters, but I don't want lower/uppercase to be separated.

What I don't know is 1) how come this lower/uppercase treatment does not happen in my regular Thunar display, 2) why there is this discrepancy between the OPEN/SAVE behavior and the regular Thunar.

Here is my "locale" output:

LANG=en_US.UTF-8
LANGUAGE=en
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=en_US.UTF-8
LC_TIME=en_US.UTF-8
LC_COLLATE=C
LC_MONETARY=en_US.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=en_US.UTF-8
LC_NAME=en_US.UTF-8
LC_ADDRESS=en_US.UTF-8
LC_TELEPHONE=en_US.UTF-8
LC_MEASUREMENT=en_US.UTF-8
LC_IDENTIFICATION=en_US.UTF-8
LC_ALL=

I'm on Xubuntu 14.04.5 LTS.

Thank you.

Answer 1

Ok, well nothing new since Gunnar Hjalmarsson posted on March 14.

The answer has two parts:

1) when open/save with a program, the program itself chooses how it sorts the files shown, potentially ignoring the user's choice of sort type

2) LC_COLLATE is somehow broken in Ubuntu 14.04.

I, the original poster, did not really answer anything. I just want closure. 1) was answered by @Serg 2) was answered by @Gunnar

For those who know more than me, please make the appropriate edits and give whatever points where they belong. Thank you.