Many of the Mathematics and SIgnal Processing VIs retain state, rendering them unusable inside reentrant VIs: http://digital.ni.com/public.nsf/allkb/543589DF37BA48CF8625744A00543FF3
Many of the VIs in this list (all those in my current application, unfortunately) can only work with single-channel data. When manipulating multi-channel data, you can work around that fact by running the channels serially through the VI you need, but that (1) takes much longer for large data sets or several channels, and (2) is not an option when performing live manipulation of streaming data block-by-block.
I ran into this problem while developing code in the Actor Framework, where Do.vi and Actor Core.vi (the two main framework methods) are both Shared Reentrant. Now that AF is a native feature in LV, I expect that more people will run into problems with these VIs.
We need stateless versions of these VIs so we can use multiple copies in on a multichannel data set. You can probably keep backward compatibility by pushing the core logic to a new stateless subVI and keeping the shift register or feedback node on the main VI's diagram.
