I just did a post with a self-shortened quote in it.  On boards that have preview, I always use that function to make sure I haven’t edited out any of whatever markup language.

Here, Preview Post just shows me what I typed in:
[ quote ]This is a quote.[ / quote ]
not

This is a quote.

That’s odd. 

I thought I saw HTML tags’ effects, not just the tags, in previews last week.  I could be misremembering.

Not that I wish to murmur against Dave and recall the fleshpots of Egypt, but EZboard’s preview function is WYSIWYG: the HTML tags take effect in the preview and show you how the post will look.

I found that I was looking at the editing text area when the previewed text was above it.

As was I, he said, blushing.