Code review comment for lp:~rafalcieslak256/millenniumduel/containers

I love the code you wrote. It's elegant and very powerful, and is going to save us a lot of effort.

However, I discovered a minor bug. When examined carefully, it turns out, that buttons' click sensivity areas are a bit offset upwards with respect to their drawings.
I think I can tell which part of code needs a correction. In functions HBox::on_clicked and VBox::on_clicked, the 'sum' variable should be initialized with:

int sum = margin;

instead of actual:

int sum = 0;

Very nice job!