According to the manual, the SHOWHIDDEN option for the Select command does not take any arguments.
If I select a single file and >Select NOPATTERN HIDEUNSEL then all files and folders except the selected one are correctly hidden. I would now expect the command >Select SHOWHIDDEN to reveal the hidden items. Instead, a dialog pops up inviting me to "Enter the file extension or wildcard pattern to select files." I can type any string (or an empty string) and press Enter to reveal all. Likewise, if I >Select asdf SHOWHIDDEN, where "asdf" can be any non-blank string, all previously hidden items are immediately revealed without the pop up dialog.
The Select SHOWHIDDEN example documented in HELP does not describe the use of any pattern, or NOPATTERN, or the need for either, in combination with the SHOWHIDDEN option.
Certainly Select NOPATTERN SHOWHIDDEN works, but then so does Select some-arbitrary-pattern SHOWHIDDEN, and specifying a pattern like Select *.txt SHOWHIDDEN does not restrict the list of revealed files to those with .txt extensions.
The default behaviour of Select is to select files by wildcard pattern, so if you don't provide a pattern (or the NOPATTERN argument) it will ask for one. There's no semantic difference between SHOWHIDDEN and HIDEUNSEL - they both do things in addition to the command's primary function.
