As mentioned here: http://forum.openmpt.org/index.php?topic=4526.msg37088#msg37088

The reason that this feature must be enabled for each sample separately in Renoise is that it's expensive to compute. It is way more expensive to compute than volume updating and all the stuff OpenMPT does when jumping around in the order list. Basically said, you have to render the whole tune up to the position you want to jump to if you want to know a sample's current playback position. And this is why Renoise does not automatically do it and why OpenMPT will also not automatically do it, even if someone considers implementing this someday.

Ah, thanks for the information.

I've implemented a very experimental version of this feature, it won't work under some circumstances (e.g. when using portamentos or ping-pong loops), but I guess it's usable. Can be enabled from the general options ("Maintain sample sync on seek"). http://sagagames.de/stuff/mptrack.exe

There are still some rough edges concerning this feature (e.g. it won't work when resuming from a stopped song state), but these will be fixed in the next version. Closing this issue for now as it has been implemented.