Word-wrap at bash prompt doesn't work properly about puttycyg HOT 6 OPEN

This is unlikely to be a PuTTYcyg issue. You need to make sure you've enclosed 
any non-printing characters in your prompt with '\[' and '\]', so that readline 
can correctly calculate the length of the prompt. See also 
http://www.gnu.org/software/bash/manual/html_node/Printing-a-Prompt.html#Printin
g-a-Prompt.

I occasionally experience the same behavior, but so far I have not been able to 
consistently reproduce it, which is why I have not reported any issue.

I am using the default Cygwin prompt, as set by /etc/bash.bashrc, i.e. 
PS1='\[\e]0;\w\a\]\n\[\e[32m\]\u@\h \[\e[33m\]\w\[\e[0m\]\n\$ '

I do not see anything wrong with this prompt. Do you ?

Nope, looks fine to me to. I'd check whether the number of columns reported by 
`stty -a` tallies with the actual window size.

I have the same problem too. And I found it occurs under Win7_64 but not WinXP.

A quick but dirty solution:
Change "Property" of PuTTYcfy.exe by right click on the file, "Compatibility", 
check "Run this program in compatibility mode for", select "Windows XP (Service 
Pack 3), and then "Apply/OK".

Wish it helpful.

Update: It seems my solution yetoday will cause some weird problem. Wish anyone 
can fix the bug. Thanks.

Update2: I downloaded source code of PuTTY, and tried to have a look at the 
bug. Fortunately, I found that there is a "PuTTY wish cygwin-terminal-window
" feature in version 0.61. I tried, it works well.

Reference: 
http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/cygwin-terminal-windo
w.html