Not possible with CodeLab. In fact, it would be fairly difficult because you'd need the source code to Paint.NET in order to copy the code for the UI elements (X/Y and color wheel controls).
Maybe you could just use a drop down list box instead of a color wheel. Just make some presets including Primary and Secondary colors, red, blue, black, gray, purple, etc.
I think using tabs is a good idea, so I try to find the source for the UI controls. I managed to find the color wheel in the source of PDN 3.0, but I can't seem to find the "double vector" control (to use the codelab name, the one that selects the vanishing point), and I'm beginning to wonder if it was there in 3.0 at all, and since I don't see a later version source code I'm kinda stuck... does anybody know where I can find the source for it to include in my plugin?
I'm hoping that using the tabs will solve this. If I can't figure out how to do the plugin from outside codelab, I will use your suggestion...
You're right, you won't find an adjustable brush size in the current version. You will find it in the next version though. I already got it working, I just want to figure out the UI thing and I'll publish a version with this feature, I'll PM you to let you know when it's here, just in case..
There is a problem with this feature IMO. Let's say I will have this option, it means that the vanishing point will not be seen, since AFAIK there is no way to tell Paint .Net to show stuff outside of the Canvas. That means that the user won't be able to accurately draw more lines to the vanishing point...