Webmail compose message field width

[#1]

For the last few weeks, when composing a new message (or replying to a message) using Webmail, the compose page only opens half way across the screen, and one consequence is that the left half of the Subject field is completely obscured by the edit icons. I can't find any way of adjusting this, but just to complicate things:
1. This only happens on a Windows PC running Vista and Chrome
2. If I open Firefox on the Vista PC, initially the field opens in narrow format and then suddenly opens out to normal
3. On a Macbook running Chrome, there is no problem
4. On an Android tablet running Chrome no problem
Any ideas out there? Please don't tell me to abandon Windows equipment, my wife is a heavy user of the PC, and I'm getting grief!

[#2]

Just tried and it opens a small window then expands immediately
It doesn't happen when using Basic Webmail
On Advanced Webmail my edit icons are across the top and I can't see how to change it

[#3]

I've no problem with basic webmail either. Looking more closely at what happens with advanced webmail/Chrome, initially there's a very brief flash of the narrow format, then an equally brief flash of the wide format, then back to the irritating narrow format. With advanced webmail/Firefox, there's a very brief narrow format flash and then it settles into the wide format.

[#4]

Not quite Vista, but using Chrome 37.0.2062.124 and Windows 7 I don't seem to be able to replicate the problem
Could it be an extension or something similar that's causing the problem?

[#5]

It's happening with me too
Dell XPS12 running W8.1u1 and Chrome Version 37.0.2062.124 m. Full HD screen.
EDIT - OK in Firefox - though it displays as in Chrome for a split second then goes normal.

[#6]

Still unable to replicate on a second machine. What do peoples' compose settings look like?

[#7]

Still happening - sorry didn't see above request:

[#8]

Still struggling to replicate the problem, even using the same composition settings

[#9]

One thought for those with the problem,  does anything interesting appear in the Javascript Console (Ctrl+Shift+J).
And on that note, does anybody else get the following error in chrome

Quote

Uncaught SyntaxError: Unexpected token <                /missing.php:2

which appears to be caused by attempting to load https://webmail.plus.net/skins/RoundcubeSkinPlusnet//www.plus.net/js/xtcore.js

[#10]

Quote from: kmilburn

And on that note, does anybody else get the following error in chrome

I see a similar error using Firefox's developer tools. I /think/ it's something to do with analytic tracking, shouldn't think it would result in the problem being reported.

[#11]

I've managed to reproduce this on Win 7.
Don't maximise the Chrome window if you have a large screen - you may have to make the window narrower to see the effect.
Drag the divider between the attachments pane to the right. When the Edit identities on the From: line breaks across two lines you will see the problem.
It's to do with the height of the headers above the compose box.

[#12]

@drj
Have you got a very long identity name in the From drop down box? That box automatically resizes to fit the longest name, so if you have a long name in the list it makes it more likely the "Edit identities" will wrap.

[#13]

I still can't replicate it, even with a ridiculously lengthy from identity

[#14]

The longest of the four registered is D**** J****<D****.J****@xxxxxxxxxx.org.uk> - not overly long?

[#15]

Quote from: jelv

I've managed to reproduce this on Win 7. Don't maximise the Chrome window if you have a large screen - you may have to make the window narrower to see the effect. Drag the divider between the attachments pane to the right. When the Edit identities on the From: line breaks across two lines you will see the problem. It's to do with the height of the headers above the compose box.

Yes - tried that using FF on XP on my desktop and exactly the same overlapping results as your screenshot.