Collecting information about exporting large package has a huge delay with confusing "Nothing to export" message

How we can reproduce it using the example you attached
1. Open/import large package (~500MB, I've used SECTR COMPLETE).
2. On Assets press right mouse button -> Export Package...

Actual result: You'll see exporting window with message "Nothing to import!", and in about 10 seconds the tree of assets. Message can confuse user.
Expected result: Users see loading wheel or something similar and message "Please wait, collecting information about package".