The Toolbox parses a spec upon opening it. The parse status of the currently open spec is shown in the lower right-hand corner of the Toolbox window. The status is either: Parsed, meaning it has no parsing errors; Unparsed, meaning that the spec had no errors the last time it was parsed, but that one of its files has since been modified and saved; or Error, meaning that an error was found the last time it was parsed.
Clicking File/Parse Spec parses the spec. Clicking File/Parse Module parses the currently selected module, which is the one in the most recently selected module editor. Parsing the spec is equivalent to parsing its root module. Unless your spec is VERY BIG, you will want to parse whenever a module is saved. See the parsing preferences listed below for how to do this.
If there is a parsing error, the Toolbox pops up a Parsing Errors view. For most errors, clicking on the error takes you to its location in a module editor. The Toolbox also marks the locations of the errors in the module editor (or editors). There is a preference, described below, that controls whether or not the Parsing Errors view automatically pops up. If you set it not to pop up, you can open the view from the Toolbox's Window menu.
Causes a module to be reparsed when you save it from the module editor. It is the default.
Causes the entire spec to be reparsed when you save a module, if that module is part of the spec. More precisely, the spec is reparsed if the Toolbox found the module to be part of the spec when the spec was last parsed. This option has no effect unless the Re-parse module on save option is chosen. It is the default.
It is the default.