JOSM should not make me wait for up/downloading data

[xeen]

Downloading or uploading data makes you sit in front of a progress bar with nothing useful to do. I'm not sure if this is avoidable for "normal data" because of collisions (i.e. uploading data, while editing it.), but it sounds safe to implement this for the GPS download dialog.
Only problem with "hiding" the dialog is that there's no place to display an error message if the download failed, and popping it up from nowhere doesn't seem too good either. Maybe displaying a note in the "map area" might work, at least it shouldn't take up any permanent place.

[xeen]

While experimenting around I found that GPS tracks can be easily downloaded in be background because map view works asynchronously anyway. I'm unsure about a good UI though and wonder if it's even wanted to implement parallel downloading because of the additional stress put on the servers…

[Candid Dauth]

This would also be great for importing images, which usually also takes quite a while. It should be easy to allow working in the main window while the progress popup is open, as it works with the relation-editing popup and the photo-viewing popup, too.

[xeen]

Nah, it's the image importing function that's really, really slow. Try the AgpIfoJ plugin, it's much faster :)