IE9 Inheritance of doctype breaks FCKeditor

[Alfonso Martínez de Lizarrondo]

In IE9 there's a bug where the rendering mode is based upon the topmost doctype, so if the main page is in Standards mode, then the FCKeditor fckeditor.html page that uses a quirks mode doctype will behave wrong (the toolbar buttons are displayed as a big mess at the top left)

I've added a comment in ​the MS connect site

[Jakub Ś]

@alfonsoml I've taken a liberty of quoting your comment from #8161

I think that it might be related to ​https://connect.microsoft.com/IE/feedback/details/599022/canvas-element-unknown-in-iframe-if-no-doctype-on-parent-page-ie9p5

In IE9 it's not good idea to mix quirks and standards pages (iframes), because they won't behave in the way that it's expected, and IIRC, even some js tests will fail stating that the rendering is done for example in standards mode but the reality is that they have been forced to quirks (or the other way around).

There's no reason to use Quirks mode except while supporting very old sites, and in those sites the developer can add the X-UA-Compatible header (and forget about using code with new features)

FCKeditor is no longer supported. If anyone wishes to use IE9 with FCKeditor he/she should do as stated in last part of @alfomsoml comment - use X-UA-Compatible meta tag. Example can be seen below:

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" /> 

[Alfonso Martínez de Lizarrondo]

Thanks, I wanted to close this one but I forgot :-)