It still dosn't clear

You seem to like to use the array form for the -command. The code I showed you does NOT have the brackets.

-command => [$right_frame => \&clear_file])
#notice the difference
-command => \&clear_file )
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Don't use the bracketed command form unless you know what you are doing with it. It is used if you want to pass arguments to a subroutine, which you don't need in this case.