Code review comment for lp:~alan-griffiths/mir/fix-1516670

Having a stack of overlapping fullscreen surfaces in the host server introduces some visual artifacts (and inefficiencies).

So this is clearly not the ideal solution - just less broken than what we currently have.

There are a number of approaches for a better solution:

1. use non-fullscreen surfaces in nested mode and either:
1.1. display only the intersection of all outputs
1.2. display the bounding rectangle of all outputs

2. use only fullscreen surfaces and either:
2.1. select the "smallest" display
2.2. select the "largest" display

I'm not yet convinced by any of the above options, but favour of sticking with "fullscreen only" when nesting.