New utility method [1781]
Ensure chosen files make sense as a set, to create a single SNPP data source [1781]
Very minor - just eliminate one unneeded method call [1781]
Allow aggregations of different products (e.g. M3,M4,M5) [1781]
Make sure selections deliver full-res data [1540]
Enable "Add Source" button upon restart. [1074]

There appears to be some weirdness with properly restoring the
TLEChooser’s file selection…but I’ve been banging my head against this
one for too long.

Notes about the issue are in the comments of TLEChooser.setSelectedFile.
Utility methods for working with component trees.

[0]