There is no need to clear every line entirely before drawing to it, this

means moving the cursor and messes up wrapping. Better to just clear the
sections that aren't written over. GitHub issue 2537.

tmux.h

@@ -1890,7 +1890,6 @@ const char	*find_home(void);
 const char	*getversion(void);
 void		 expand_paths(const char *, char ***, u_int *);
 
-
 /* proc.c */
 struct imsg;
 int	proc_send(struct tmuxpeer *, enum msgtype, int, const void *, size_t);