I am using Firefox for development of Apex applications. I have my builder open in one tab and the application in the next one. As soon as I make a change I would switch to the application tab and see the results after reloading or submiting the page. That is quite practical and saves a lot of clicks. Couple of days ago I was developing an application and had to rename a page item. This item was involved in some page computations and after renaming it the page didn't work the way I expected. I spent probably an hour trying to understand why. I changed my code couple of times withouth success. Then it came to my mind that I had seen this before. I logged out, logged in again and my code suddenly worked. So, this is just a small tip to first logout after renaming page items. It could save you a lot of time (and nerves) if you remember it.