Wrong texture colors

[Leon23423465]

SLADE Version: (3.X.X.x) Operating System: (Windows/Linux/OSX)

Issue Details: When I copy texture from some wad to another, I go in my new wad where are copied textures and I colourise it in any color. When I run wad, textures are tottaly glitched. Colors are mostly white, which was not meant to be.