This has been a big annoyance for me. I do a lot of 3D print work where I need to be painting and sculpting at the same time, turning colorize off helps to see the forms better while sculpting, but if I want to Remesh, I have to turn colorize on then do the ctrl+drag. (I ended up making a macro button to do the same thing, but this is still a somewhat slow workaround.) Often it will cause me to even end up doing a bunch of work and then realizing I had lost my Polypaint information, since ctrl+drag becomes a force of habit in ZBrush after a while.
It seems weird that ZBrush would just delete Polypaint information just because Colorize isn’t on, it’s still part of the mesh data, you’d think there would at least be a warning like when you hit the Delete button on the Subtool palette.
The default behavior should just be to keep the Polypaint always, if someone doesn’t want their Polypaint information anymore, then they would simply do a fill color or clear, they wouldn’t turn colorize off and Dynamesh to do that… But an option for it would be fine too.
cheers.