Incorrect on_clicked propagation by HBox and VBox.

[Adam Malinowski]

In function

HBox::on_clicked

there is a piece of code:

    for(auto i : children){
        sum += i.size;
        if(p.x <= sum) { // This item was clicked!
            i.item.on_clicked(SCoordinates(p.x - sum, p.y));
            return;
        }
        sum += spacing;
        if(p.x <= sum){ // Empty space between items was clicked
            return;
        }
    }

It probably causes click event to be propagated to item i with wrong coordinates. Line

            i.item.on_clicked(SCoordinates(p.x - sum, p.y));

should be replaced with

            i.item.on_clicked(SCoordinates(p.x - (sum - i.size), p.y));

or, more elegantly, addition to sum could be delayed:

    for(auto i : children){
        if(p.x <= sum + i.size) { // This item was clicked!
            i.item.on_clicked(SCoordinates(p.x - sum, p.y));
            return;
        }
        sum += i.size;
        sum += spacing;
        if(p.x <= sum){ // Empty space between items was clicked
            return;
        }
    }

The same bug affects function VBox::on_clicked.

[Adam Malinowski (adayah)]

Note: this bug had not been discovered before, because we had only used buttons inside Boxes. Buttons do not care about the coordinates they're clicked at.