I guess I’ve found a strange bug.
Tested on Ubuntu 16.04 and Mint 18.2: when dragging a file which name is composed of the “+” character (“hello+world.bin” for example), the file received in Juce is the same but with the “+” replaced by a whitespace (“hello world.bin”).
Obviously, it makes the use of this File fail, as it doesn’t exist.
I tested on Windows, no problem. Didn’t test on Mac, though.