Change window (open/closed) preferences to persist between boots

[adamkewley]

Estimate: 2-4d (it also requires robustly implementing a long-term per-user configuration system)

At the moment, if the user opens/closes windows it isn't remembered between boots of the application. This makes the UI feel a little less "homey" because the user may have set things up just how they like it to find that resetting the application wipes all memory of their changes.

[adamkewley]

#782 implements most of the underlying infrastructure that this issue required, so I imagine sorting this out is going to be acouple of hours, maybe a day, rather than a few days.