File upload attempt attempt hangs without information
Attempting to upload a file to the server results in the "File Transfer" window being shown, with "Uploading via HTTP File Upload". The sliding decoration at the bottom briefly animates before the application freezes. Painting of the application windows cease. The application can be resumed by clicking the the File Transfer window, or, if the Cancel button is still visible, clicking Cancel. No output is given on the console.
It would be good if the application did not become unresponsive and cease to paint the windows, and information were provided to diagnose the problem.
This is tested with gajim and plugins version master HEAD (1.4 development) from 2 days ago.