pgadmin4 command keep running and process watcher won't go away

I was trying to follow the instructions from postgresqltutorial to load a sample database into postgresql using pgadmin. But after the database was restored(since I can query data from the database), the process watcher just won't go away, and it keeps saying that the command is "running"(as of this writing, it has been running for over 400 thousands seconds, but the size of the sample database is just a few megabytes). Reboot and reinstallation couldn't fix the problem.

I posted a question on stackoverflow with some screen shots: http://stackoverflow.com/questions/39868220/pgadmin4-command-keep-running-and-process-watcher-wont-go-away

I first encountered the problem with postgresql 9.6-rc1, but then I deleted the database, uninstalled postgresql 9.6-rc1, and installed postgresql 9.6, but after I opened pgadmin, the process watcher is still there, and the running time just added up.

I am using pgadmin4 on windows 10, since I am a beginner, every setting is by default.

So what seems to be the problem here and how can I get rid of it?