Thanks! Tested 44.0.0.14 and it's working fine
As for the second problem, I've found an easy workaround for Windows. If you want to do e.g.
mkvmerge -o "D:\path to\foo.mkv" "D:\path to\foo.264" --title bar using GUI and doesn't want to get bar.mkv, you can just change one character - lowercase the drive letter - in the Destination editbox: "
d:\path to\foo.mkv" instead of "
D:\path to\foo.mkv".
Of course, one can also use Multiplexer | Show command line, and just paste it to cmd.exe or make a batch file (which is most convenient for me).
One cosmetic observation: the command line generated by GUI for cmd.exe uses forward slashes to write a path to the folder where mkvmerge.exe exists. E.g. if you have mkvmerge.exe & mkvtoolnix-gui.exe in
D:
\folder
\mkvtoolnix
then, a command line generated by GUI looks like:
D:
/folder
/mkvtoolnix\mkvmerge.exe --ui-language en --output ...
This seems harmless, though, as cmd.exe now accepts a forward slash as if it were a backslash.