Take a look at property editor. Some properties can be changed in "value" column only, but others are more complex and the value column shows dropdown box leading to modal window with more appropriate editor.

Editing these complex properties straight in the value box is not probably the best practise - there is better editor to do that. In this case, such properties should be edited only in the modal window editor and the value column should be read-only (it can show part of the value so that user can see if the value has been filled in or not) with edit icon on the right side leading to that modal window editor.