Moving lifelines and extending diagram gates

[Blade]

When I insert a lifeline, sometimes it will not let me move this to below part of an interaction diagram which is a WIP. Without this, I will overrun the margins of the page and the model will not be practical to put in my word document.

Also, when I insert a diagram gate, how can I change its dimensions? The appropriate cursor to make it bigger appers, but nothing happens. In some diagrams in the help guide, the diagram gate has been extended.

Thanks