@marceloexc Hmm... would be possible (as long as it's a gradient along the y axis; the way I optimized window decorations forbids any changes alongside the x axis for now).

@marceloexc basically anything that can be implemented as four corner textures (which may overlap the window) plus for border textures (which will be stretched along the edges of the window) would work. The titlebar is baked in to the decoration texture. The titlebar text drawing code understands a titlebar-content-height and titlebar-content-y-offset, so it can support basically all titlebar styles were the text is centered in the middle. Even ones overlapping the window itself.