This is mostly aimed at osu! mappers/storyboarders who need an easy way to access osu! beatmap folders through wine.
This is a quick tutorial on how you can edit some wine registry files to make wine open the native linux file explorer when clicking the Open folder menu on whatever application uses it, since the explorer.exe application doesn't integrate that well with the linux environment.
The main use-case for this workaround is the case of those who need to work with a high bandwidth of files being moved around and shared/edited/whatever it's needed to do with it. eg. osu!mappers
First of all, you need to locate the path to your osu! prefix:
- for people using the 
osu-winescript, by default it's located at~/.local/share/osu-wine/WINE.win32; - for people using lutris, it is asked to the user at the beginning of the installation process the path they wanted to install osu to;
 - if you have a custom prefix, you may know its path.
 
Many osu! players use custom wine builds to achieve better audio latency, if you happen to do so, please get the path of the custom wine build.
We will create a shell script on ~/.local/bin/ named run_as_linux:
#!/bin/sh
truepath="${2%?}"
unixpath="$(printf '%s\n' "$truepath" | sed -e 's/\\/\//g' -e 's/^.://'; echo x)"
unixpath="${unixpath%?x}"
exec "$1" "$unixpath"- Remember to replace 
/path/to/custom/wine/with your custom wine path. If you're using the system wine, replace it with justwine; - After finishing saving the file, remember to set its permissions correctly 
chmod +x ~/.local/bin/run_as_linux. 
Now we need to set up the wine prefix to call the wrapper from the application running inside it, to do that, we will create a new registry entry for the Open folder command.
After opening wine registry (regedit) with WINEPREFIX=/path/to/osu/prefix wine regedit, we will do the following steps to create the association with the wrapper:
IMPORTANT: Remember to replace /path/to/osu/prefix with the path of your osu! installation wineprefix.
- Create a 
commandkey insideHKEY_CLASSES_ROOT\folder\shell\open; - Delete the 
ddeexeckey inHKEY_CLASSES_ROOT\folder\shell\open; - Set the 
(Default)value to/bin/sh run_as_linux NATIVE_FILE_MANAGER "%1"; 
IMPORTANT: Remember to replace NATIVE_FILE_MANAGER with your native file manager binary (eg. nautilus, dolphin, thunar, etc.) or xdg-open.
Now you're able to open your beatmap folder (or every other folder) into your native file explorer from osu!
Why put the script in
/usr/local/bin/? Why not~/.local/binwhich is easier and safer to deal with as you don't need sudo priviledges for it (and would work on immutable distro).