When you are editing 4DScript code, ED automatically inserts the ) when you type (. Sometimes that's nice, but sometimes it isn't. In those cases you can disable the feature by going to the Editor section of the menu and unsetting the AutoBrackets checkbox.
It is also possible to turn off the behavior where ED selects the whole block when you press Backspace on a closing ).
If you would like to change the colors used in ED, go to the Appearances section of Preferences. Click the button to create your own color scheme, then change it at will. For instance, it is often nice to use a striking color for the editor's Matching Brackets. This makes it easier to see where code blocks start and end.