Not sure if this is related, but I had an issue where if I gave a path to the FileDialog it would grind away for a few seconds because it was somehow interpreting it as a network path. To fix this I gave it a path that had a prefix of "file://". To accomplish this I did this:
QUrl().fromLocalFile(cell_info->progDir()).toString()The original path came from cell_info->progDir(). Somehow that path was a regular windows specific path. Once I wrapped it in the fromLocalFile call it produced what I needed for all platforms I was using it with.
Again, I have no idea if this is related to your issue, but it sounds fishy like it is grinding away in the background on something. If this is not related feel free to ignore my comment.