The iframes are used for file upload requests and also as a fallback for XHR (the latter is pretty much historical). popin.html is the default page template for dialogs and pop-ins.
I'll try to eliminate the redundant server requests - or at least make them happen only if they are needed.
Regarding application loading, there's no easy way to accomodate your request, because dependencies are currently discovered in run-time (the first portion of the application has to be loaded in order to discover which additional portions are needed).
We have a plan to improve this mechanism (using static analysis or by recording actual dependencies), but this is currenly not a priority.
There's a simple hack we can add quite easily, which can help optimize initialization:
We can add a way to the specify the list of packages loaded initially (as opposed to dynamic disovery or 'all'). You will be able to experimentally discover the appropriate set, and then you'll have a shorter start-up time (but subsequent actions might still require incremental dowlonading and dependency discovery).
If you think this will help - let us know.
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