skip-whitespace error on "I" command at end of line

[takikawa]

With the buffer as abcdefg and with the cursor on g, type the "I" command. The following error is returned:

skip-whitespace: called on a color:text<%> whose colorer is stopped.
  context...:
   /Users/user/Library/Racket/8.18/pkgs/drracket-vim-tool/private/text.rkt:421:6: handle-command method in ...ool/private/text.rkt:61:4
   /Users/user/Library/Racket/8.18/pkgs/drracket-vim-tool/private/text.rkt:136:13
   /Applications/Racket v8.18/share/pkgs/gui-lib/mred/private/wxme/editor-canvas.rkt:504:2: on-char method in editor-canvas%
   /Applications/Racket v8.18/collects/racket/private/more-scheme.rkt:148:2: call-with-break-parameterization
   /Applications/Racket v8.18/collects/racket/private/more-scheme.rkt:266:2: call-with-exception-handler
   /Applications/Racket v8.18/share/pkgs/gui-lib/mred/private/wx/cocoa/window.rkt:892:4: dispatch-on-char method in window%
   /Applications/Racket v8.18/share/pkgs/gui-lib/mred/private/wx/common/queue.rkt:436:6
   /Applications/Racket v8.18/share/pkgs/gui-lib/mred/private/wx/common/queue.rkt:487:32
   /Applications/Racket v8.18/share/pkgs/gui-lib/mred/private/wx/common/queue.rkt:639:3