Fatal Error (line==NULL in terminal.c) when opening Urls menu

[ghost]

Hi,

I get seemingly random Fatal Errors with Urls menu. It seems to have something to do with resizing the window. I cannot reproduce the issue consistently, but every time I could, it's after resizing the window.

Environment
PuTTYTray p0.67-t029
Windows 10 Pro (1709 build 16299.15)

Steps to reproduce
I cannot reproduce every time, but whenever I could, it's been with the following process:

1. Open PuTTY Tray and connect to server

2. Get some content with URL(s) to the window.
   Originally I ran into the error with mutt email client open with some urls in an email. Any content with urls could work. I have been able to reproduce with mutt, and with for example irssi status window which has an url on it.

3. Open Urls menu. It should show the urls as usual.

4. Close Urls menu.

5. Resize the PuTTY Tray window. For example just widen the window by a couple of pixels

6. Open Urls menu again.
   Get an error popup:

PuTTY Fatal Error
line==NULL in terminal.c
lineno=5579 y=26 w=82 h=24
count(scrollback=04D103E0)=49
count(screen=04D10440)=24
count(alt=04D55830)=24 alt_sblines=0
whichtree=04D10440 treeindex=26

Please contact putty@projects.tartarus.org and pass on the above information.

OK

7. Press OK and the error and PuTTY Tray close. You lose the PuTTY Tray window and connection.

[FauxFaux]

I can't reproduce this here with the new version; the window won't go small enough. I can see how this could happen, the use of lineptr() in the URL code is a bit scary.

I'll have a think about the indexes and see if this can be done better.