Troubleshooting does not work

I can enter troubleshooting mode and in the beginning, I was able to play around with enabling and disabling various plugins in this mode. But then, suddenly, it stopped working. Now, I am not able to leave troubleshooting mode anymore (except for cleraing cookies) and also enabling plugins in troubleshooting mode does not work anymore. If I click on the corresponding button or links, the site refreshes, but that’s it. Nothing happens, nothing changes.