Single-click on results
A single click on results selects the underlying item.
Double-click on results
Typically, a double-click on results opens the content for editing - if the GN4 application features editor for the given content.
If you double-click an article, listed in the results of the Articles navigator on the Articles main tab, the article opens for editing. The same works for pages, listed in the results of the Pages navigator on the Pages main tab, and for other similar content (editions, tracking layouts, publishing destinations etc.).
If there's no specific editor, then the editing form is displayed, e.g. for tasks, listed in the results of the Tasks navigator on the Articles main tab.
For other content, double-click may have no effect.
Right-click on results
Typically, when you right-click results, a pop-up menu is displayed with options that apply to the selected item(s).
See also
Linking mouse actions to results