The Spacing options page specifies space insertion rules for the Code Formatting tool.
The options page is language-dependent. It means that the options set depends on the currently selected language.
Each tree view item specifies whether CodeRush adds a space at each occurrence of a certain construct or not. To clearly see how the current option affects your code, look at the code example at the bottom of the options page.
Note that if the Keep existing whitespaces option on the General options page is on, CodeRush leaves white spaces in existing code regardless of the specified Spacing rules. In any case, the rules affect newly generated code anyway.