1/ While writing a new post or a response, the keys used to navigate between browser tabs are intercepted by the forum software, making it very difficult to quote from another tab. Worse, there is no information available what those keystrokes DO in the forum! 2/ Way too easy to accidentally post an incomplete message, e.g., by pressing a key intended for screen navigation. Also easy to lose an already composed multiparagraph message while attempting to find some information in another tab or another window. The keystroke (ctrl-Z) which in other composition programs reverses the last action (usu. referred to as undo), such as deleting the last few characters typed, often deletes the whole text entered - an action that's easily performed in a different manner that explicitly selects what is to be deleted. There is no redo to reverse an incorrect change or one made by accidental pressing of a single wrong key.