Thanks.  FWIW, I noticed this regarding the issue in 5.0.7:

If I open a .PL file by double-clicking on a file in Windows File Explorer or
from FileZilla, it opens the file in PSPad (PSPad is associated with the .PL
extension) and the key mappings work fine.  I made sure it was opening the 5.0.7
version in this case.

If I open the PSPad 5.0.7 application first without a file using a shortcut on
my desktop, THEN use CTRL+O to select a .PL file to open from within PSPad, then
key mappings don't work.

Hope this helps!

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