Holy crap, we have in-context position and resize! No more position and size in the widget editor. No more preview in the widget editor for slideshows (you can already see all the images in order). Note that the resize corner is hard to see on our current background. In general, the margin of a widget should probably be visible somehow during editing.
Resize and position dynamically in the main content editor, etc. rather than the widget editor. UI darkness rather than lightness to match our current sandbox, for now.