Drag and drop from Explorer not working in Release mode - VS 2019/Win10

We’re just working on the finishing touches of our JUCE app so we can release it on Windows.
It’s been out on the Mac for several months already.

While testing we found that drag&drop from the Explorer doesn’t work on Windows in Release mode. Everything works fine in Debug mode but it looks like our app doesn’t get any mouse drag events from the Explorer in Release mode.

We tried to find the reason for this and we’re completely tapping in the dark. The only thing we could find is that Windows seems to prevent drag&drop between apps with different permissions - an app with elevated permissions can’t receive drag events from another with a lower permission level - seems to be a security measure. But first of all we’re not running our app with elevated permissions and second this would not explain why it behaves differently between Debug and Release.

If anyone has an idea of what we could try, please let us know!
We have hit a brick wall with this and we are really clueless on what to try…

Thanks in advance!