Make Site Layout default option when selecting Appearance option

When selecting Appearance option from OSc toolbar, Themes is the default option.

Site Layout, however, is something that is accessed far more often, in my own case, and I would imagine others, as it provides so many options for different elements of the site.

Themes, by contrast, provides just one option: to change the theme and I would think this will not happen repeatedly.

Moreover, at present, each time Appearance is selected, it 'rustles' through the various themes until stopping at your selected one. This is quite attractive, but largely a waste of time!

Thus it makes sense to make Site Layout the default option when Appearance is selected from the toolbar.