Text in a placeholder opened in the editor looks differently as in the preview mode.
A possible cause is the usage of CSS styles directly in the template, instead of in external .css-files. For example:
<Axinom:AxContentPlaceholder runat="server" ID="basePlaceholder" />
The text editor loads all the css-files defined in the template, but not the inline styles.
Extract all CSS-related information into .CSS-files and add them to the template using link-element:
<head id="headTag" runat="server">
<link href="~/templates/CSS/myCss.css" runat="server" rel="stylesheet"
Define the classes available for the editor with HTML-rules in CmsSite.xml under <HtmlRules>.
<HtmlRule axid="default" tags="STRONG,BR,OL,UL,LI,EM,U,HR">
<Tag name="SPAN" styles="default" />
<StyleDefinition axid="default" values="">
<Value value="headline" ribbonImage="/images/RibbonImages/Styles/headline.png" />
You can even attach an icon for every class – the icons will be shown then in the ribbon toolbar (attribute ribbonImage above):
What you see in the editor is pretty much the same what you see on the page, but it is not 100% the same – it has a different context, it sits in a different HTML page (otherwise you cannot edit the text with a fancy editor). It means that there are chances – in spite of all our efforts – that there will be some visual differences, which an Editor has to accept.