I've been working with 2.5-M2 and noticed an interesting thing with
idMemoize and RequestVars.

I have a snippet like this:

object Count extends RequestVar[Int](0)

object Memoize {

  def incrementCount = {
    val count = Count.is
    Count.set(count + 1)
  }

  def render = {
    "div" #> SHtml.idMemoize(in => {
      "@count *" #> Text(Count.is.toString) &
      "@refresh [onclick]" #> SHtml.ajaxInvoke(() => {
        incrementCount
        in.setHtml()
      })
    })
  }

The first time refresh is clicked a 1 is displayed in count, as you would
expect. However, the second time it's clicked a 1 is still displayed, not
what you would expect. The third time it displays a 2. This doesn't happen
in 2.5-M1. Maybe I'm missing something ...

My use case for doing this type of thing is putting the IdMemoizeTransform
into a RequestVar so I can share it across Snippets.

Here is a sample project to run the example:

https://github.com/kaiserpelagic/lift-example