All tasks that may potentially take a bit of time to perform or that may not finish at all because a database connection has dropped are executed in the background so that you can still do other things. You can see that background tasks are running by looking at an indicator icon in the status bar.
If there are tasks running, the indicator icon is animated, showing a spinning pattern.
You can see exactly which tasks are running by clicking on the icon. This opens the Task Manager window.
You can abort a long running task by clicking the Stop button next to the progress bar.
If the task did not complete because the connection dropped, you also need to reconnect to the database. If this happens frequently, you can enable Connection Keep-Alive to send a dummy SELECT statements to the database occasionally to prevent time-outs.