[dracodoc]

In fit page mode, if the page width is less than screen, there will be a gray margin on side. I think it will be lest intrusive to just display that margin in white, like how the original software does.

Besides, maybe somebody already said this:
I'd like to have the option to define some margin even in fit page mode, that means not using up all screen pixels, because it will look better with some margin in edge. Right now it is too close to edge.