Please let me combine directories with wildcards when saving screenshots automatically

[pipe]

I want to save screenshots automatically, and I want a structure such as:

screenshots/%Y/$name_%NNN

I expected to be able to use the "Directory" selection popup to select a base directory (in this case, /foo/screenshots), and then enter "%Y/$name_%NNN" as the pattern, but it does not let me do that.

When I type '/' I get a small warning saying "Reserved character '/' is not allowed to be in a filename.".

While this warning is technically correct, it still feels like an oversight. Is it possible to have that restriction lifted, so I can put screenshots into directories by pattern?

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Shutter 0.93.1, Rev.1278, Debian Stretch, Gnome <something>