Problem: Ranges for arguments, buffers, tabs, etc. are not checked to be
valid but limited to the maximum. This can cause the wrong thing
to happen.
Solution: Give an error for an invalid value. (Marcin Szamotulski)
Use windows range for ":wincmd".
Problem: Using a range for window and buffer commands has a few problems.
Cannot specify the type of range for a user command.
Solution: Add the -addr argument for user commands. Fix problems. (Marcin
Szamotulski)
