Component vs full URL
Encode component escapes everything except A-Z a-z 0-9 - _ . ! ~ * ' ( ). Use it for a single query value or path segment. Encode full URL leaves : / ? # & = alone so a whole URL stays usable. Using the full-URL mode on a value that contains & is a common bug, because the & then splits your parameter in two.
+ or %20?
HTML forms (application/x-www-form-urlencoded) encode spaces as +. In paths, + is a literal plus. Tick "Space as +" only when you're dealing with form-style query strings.
FAQ
Why does decoding fail with "URI malformed"?
A % sign must be followed by two hex digits. A literal % in the text must itself be encoded as %25.
Are repeated parameters supported?
Yes, the parser lists each occurrence (e.g. tags=a&tags=b) as its own row.