Using while in editor creates loading bar

[spherous]

I thought this was caused from using the sync version (because it'd be blocking), so I swapped to the async call and it still does it (seems that Windows async isn't async at all and only calls through to the sync?????? Why the heck even have async if it's sync?).

This only happens in the editor, not in a build, and it's extremely annoying because it just gets in the way.
We're using this for a dev facing tool to save/load maps into our custom level editor. As soon as the file browser window closes, the loading bar goes away.

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