FreeCommander XE 2023 Build 887 64-bit donor: Cannot input characters in 'Search files/folders', 'Multi rename', and 'Quick starter' windows when they are used as shortcuts.
I find it very efficient to assign shortcuts to keys such as backslash and the pipe symbol in FC. For example, try assigning backslash a keyboard shortcut to the Quick Filter... you may find you love it and find using FC even more efficient!

This is especially handy for people who have challenges pressing more than one key at a time (accessibility for the disabled).
There is an issue, however, that the text input fields in the 'Search files/folders', 'Multi rename', and 'Quick starter' windows will no longer allow the user to enter those characters. In the latter window, it's not too important, but in the first two windows, it can be quite important.