It would be good to arrange for an option in which the End key exits the auto-completion menu and brings the cursor to the end of the line, instead of taking one to the last entry in the auto-completion menu.
When using TeXstudio, whenever the auto-completion menu appears but I don't want to use it, I use the Esc key to exit the menu. However, a common mistake for me is to try and use the End key in hopes of getting to the end of the line, while ignoring the auto-completion menu. This is very common immediately after already using the auto-completion menu for adding a command with parameters, such that the auto-completion feature leaves you in between the curly brackets. After you write between the brackets whatever you want, you wish for the cursor to arrive at the end of the line so you can continue writing from immediately after the closing curly bracket.