PuTTY
Submitted by Bram Schoenmakers on 13 May, 2009 - 11:23.
For a little while I use xdebug and vim in order to debug PHP code (see the vim-debugger module). With the F2, F3 and F4 keys you can step through the code. However, all of a sudden the functions keys did not do what I expected. With every function key I pressed vim complained with:
E21: Cannot make changes, 'modifiable' is off