You can control the wrapping html element that will be outputted in edit mode like:

@Html.PropertyFor(m => m.MainLinksHeading, new { customtag="span" }) 

The disadvantage of using span as customtag could be that in this case you may get invalid HTML in Edit mode, since span tag should not wrap other block tags like div, p, etc

So it depends on what is rendered in that wrapping tag in your case.

Other way is setting CSS class for wrapping element using EditContainerClass property:

@Html.PropertyFor(m => m.PropertyName, new { EditContainerClass = "YourInlineBlockStyle" })

Here you specify custom YourInlineBlockStyle CSS class for wrapping element in Edit mode.

Add that class in your site CSS and set display type:

.YourInlineBlockStyle
{
    display: inline-block;
}

All wrapping elements in Edit mode will have epi-editContainer class if you don't specify it explicitly.

That does indeed solve my problem. The textbox only resizes on lost focus, but it's good enough, at least it lines up correctly now.

Where are these properties documented though, what else can you set/tweak?

Thanks.