Reason for variation in unicode display between IE7 and IE8 ?

Given 2 systems both running Win XP SP3 fully patched ...
One system has IE7 fully patched and Firefox 3.6.
Other has IE8 fully patched and Firefox 3.6
On both systems the Lucida Sans Unicode font is installed and both installations of IE have the SAME settings for Encoding (UTF-8) and for Internet Options / Fonts.
On both systems, Firefox displays the unicode characters I require, correctly. These are in the 25xx (geometrical shapes) and 27xx (dingbats) ranges.
The system running IE7 also displays ALL the required unicode chars correctly.
The system running IE8 displays SOME 25xx chars but NO 27xx chars.
With Firefox providing a good control, this is weird.

Is there something different about IE8 that I need to set ... an addon may be ? What could be the reason for this difference in behaviour.

thanks RR
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When you run IE8 the first time, you are asked some questions, one of them being whether it should be using compatibility view or not. If you don't use compatibility view, things can be displayed differently from the previous version of IE. If you select compatibility view, it should display as it used to.
RetroRockerAuthor Commented:
Rindi : thanks for the comment. I have experimented with compatibility view during my efforts to resolve this. Unfortunately this doesn't make any difference to this particular unicode display problem which seems to be solely an IE8 issue. Any others with unicode display problems in IE8 ?

thanks RR
RetroRocker--Perhaps this is only saying what has already been said.
IE8 requires coding different than IE7.  IE8 is more "standards compliant" than IE7.  That means MS designed IE8 to catch up to the coding used by most other browsers.
You can make IE8 see things in IE7 mode by using compatibility view. But if you try to see a page coded for IE7 in IE8, it may not reproduce correctly--like your missing characters.
See a better explanation here
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RetroRockerAuthor Commented:
jcimarron : thanks for the comment. I appreciate the issues about standards compliance but I don't think it is truly the issue here. The pages in question are being generated by a web application (my own), so I'm controlling what's produced.
Currently the rendering of unicode characters is correct for these pages in Firefox v 3.5.x and 3.6.x, also Opera 10.x (arguably the most standards compliant of the lot) and IE7 ... on the same systems. The only failure is IE8 and as mentioned before the 'compatibility mode' ... ugh ... has no effect on this issue.
I'm going to experiment with the 'IE7 mimic' header as in the excellent link you posted and will report back in due course. Meanwhile if anyone has any other ideas :) ...

RetroRockerAuthor Commented:
Well, I have basically found out what's going on here myself.
Essentially it appears that IE8 requires that a unicode font be present on the system which contains the actual characters being requested. You may say ... 'well that's pretty obvious' but it seems not, because it appears that all the other browsers, except IE8, can display the unicode characters I required without their actual presence in a font already residing on the system on which the browser is running. I have experimented with this and installed / removed fonts which contain some of the characters I require and observed that these then become available / unavailable for display respectively within IE8.
I am not so sure that this is a standards issue as such because for example, some might consider Opera the most compliant browser of all ... but I don't really want to go down that road :)
The only thing I would say is that it seems to make IE8 a lot less useable as a browser of choice ... from a development point of view ... because any developer would have to ensure that the font containing the exact characters they require to display was installed on all user's systems.
While jcimarron's comment didn't answer the question as such, it was instrumental in leading me towards a solution. I have allocated half points on this basis.

thanks RR

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RetroRocker--Thanks for sharing the fix with us.  
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