is there something peculiar about a render :update block ?

When doing RJS stuff of the form below, I seem to recall unexpected behavoir where if I had many method calls within that block things didn't work as expected and variables would not have values I expected. I know I am not being very specific and I don't have an example. I am trying to refactor some code where I have alot of code inside the block and I am affraid I am going to have the same sort of problem I used to have previously when I had written alot of RJS stuff previously.

  render :update do |page|      ...   end

Hi Jedrin,