Deluge
Hello,
I think there is a bug when multiple (well, I could try two) "Change trackers" (or "Edit trackers", not sure. I'm using localized version) dialogs are open. I could regularly close only the last opened. The rest didn't react to a click on a button. To reproduce this bug:
1. Right click on a torrent, select "Change trackers"
2. Select another torrent, right click on it and select "Change trackers".
The second open dialog should close regularly, by clicking on OK or Cancel. The first opened is not reacting to clicks, so the only way to close it is by clicking the X on the window decorator.