Hello all,
First of all I have just started to learn Zbrush so this might be something very easy but for me its frustrating as hell and can’t figure it out.
I have a tool, which is my model imported from obj format, all works fine. I have also imported as sub-tools another parts of model, still all fine. I have tried to create zipper and stripes with build in function “IMM Curve” brush and here is my problem, I create a straps than hit group split to split it from mine mesh to separate sub-tool, but part of it or in some cases whole sub-tool go kind of darken color and I can’t edit it anymore.
I just can’t figure out how to edit the thing again. It separated to few parts, I need to merge them to one and edit, but as soon as I merge it go dark and uneditable…
I hope I made sense 
Please help,
thanks.