We have different development severs and a production server. Testing is done in the development servers. As a QA engineer, I'm switching between these servers quite often throughout the day.

In Chrome, sometimes I need to reload a page a few times to get it to pull from the newly switched server.

In Firefox, sometimes I need to quit the browser in order to get it to pull from the newly switched server.

(We have small tags that indicate which server you are pulling from, which is how I know in-browser.)

Why does that happen? I'd love to know how that happens (maybe what it's called?) and what the best way to deal with it is. (I know that Firefox has an extension for domain switching; is that the best solution?)